I did, and it seems that mysensors isn’t even listening to the events generated by the GUI. See the log below.
At 23:52:48 I activate the LED strip switch in the GUI and nothing happens. At 23:52:58 I send the on command using mosquitto_pub and both the LED strip itself and HA correctly pick it up.
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140381081007888: Received {'domain': 'homeassistant', 'id': 16, 'type': 'call_service', 'service_data': {'entity_id': 'light.led_strip_3_1'}, 'service': 'turn_on'}
2017-05-14 23:52:48 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=homeassistant, service_data=entity_id=light.led_strip_3_1, service_call_id=140382314836488-84, service=turn_on>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 FORWARDING <Event call_service[L]: domain=homeassistant, service_data=entity_id=light.led_strip_3_1, service_call_id=140382314836488-84, service=turn_on>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 WRITING data: {"time_fired": "2017-05-14T21:52:48.026747+00:00", "event_type": "call_service", "data": {"domain": "homeassistant", "service_call_id": "140382314836488-84", "service": "turn_on", "service_data": {"entity_id": "light.led_strip_3_1"}}, "origin": "LOCAL"}
2017-05-14 23:52:48 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=light, service_data=entity_id=['light.led_strip_3_1'], service_call_id=140382314836488-85, service=turn_on>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 FORWARDING <Event call_service[L]: domain=light, service_data=entity_id=['light.led_strip_3_1'], service_call_id=140382314836488-85, service=turn_on>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 WRITING data: {"time_fired": "2017-05-14T21:52:48.037536+00:00", "event_type": "call_service", "data": {"domain": "light", "service_call_id": "140382314836488-85", "service": "turn_on", "service_data": {"entity_id": ["light.led_strip_3_1"]}}, "origin": "LOCAL"}
2017-05-14 23:52:48 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140382314836488-85>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 FORWARDING <Event service_executed[L]: service_call_id=140382314836488-85>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 WRITING data: {"time_fired": "2017-05-14T21:52:48.042234+00:00", "event_type": "service_executed", "data": {"service_call_id": "140382314836488-85"}, "origin": "LOCAL"}
2017-05-14 23:52:48 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140382314836488-84>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 FORWARDING <Event service_executed[L]: service_call_id=140382314836488-84>
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 WRITING data: {"time_fired": "2017-05-14T21:52:48.045921+00:00", "event_type": "service_executed", "data": {"service_call_id": "140382314836488-84"}, "origin": "LOCAL"}
2017-05-14 23:52:48 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140381081007888: Sending {'id': 16, 'type': 'result', 'result': None, 'success': True}
2017-05-14 23:52:58 DEBUG (MainThread) [homeassistant.components.mqtt] Received message on mysensors-out/3/1/1/0/2: 1
2017-05-14 23:52:58 DEBUG (Thread-10) [mysensors.gateway_mqtt] Receiving 3;1;1;0;2;1
2017-05-14 23:52:59 DEBUG (Thread-13) [homeassistant.components.mysensors] Update: node 3, child 1 sub_type 2
2017-05-14 23:52:59 DEBUG (Thread-4) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 40, value = ff4328
2017-05-14 23:52:59 DEBUG (Thread-4) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 2, value = 1
2017-05-14 23:52:59 DEBUG (Thread-4) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 3, value = 15
2017-05-14 23:52:59 INFO (MainThread) [homeassistant.core] Bus:Handling <Event state_changed[L]: old_state=<state light.led_strip_3_1=off; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, supported_features=145, child_id=1, V_STATUS=off, device=mqtt, friendly_name=LED Strip 3 1, V_RGB=ff4328 @ 2017-05-14T23:52:37.597832+02:00>, new_state=<state light.led_strip_3_1=on; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, max_mireds=500, child_id=1, rgb_color=[255, 67, 40], V_RGB=ff4328, V_STATUS=on, supported_features=145, device=mqtt, friendly_name=LED Strip 3 1, min_mireds=154, brightness=38 @ 2017-05-14T23:52:59.015262+02:00>, entity_id=light.led_strip_3_1>
2017-05-14 23:52:59 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 FORWARDING <Event state_changed[L]: old_state=<state light.led_strip_3_1=off; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, supported_features=145, child_id=1, V_STATUS=off, device=mqtt, friendly_name=LED Strip 3 1, V_RGB=ff4328 @ 2017-05-14T23:52:37.597832+02:00>, new_state=<state light.led_strip_3_1=on; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, max_mireds=500, child_id=1, rgb_color=[255, 67, 40], V_RGB=ff4328, V_STATUS=on, supported_features=145, device=mqtt, friendly_name=LED Strip 3 1, min_mireds=154, brightness=38 @ 2017-05-14T23:52:59.015262+02:00>, entity_id=light.led_strip_3_1>
2017-05-14 23:52:59 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140381081007888: Sending {'id': 2, 'event': {'time_fired': datetime.datetime(2017, 5, 14, 21, 52, 59, 15318, tzinfo=<UTC>), 'event_type': 'state_changed', 'data': {'old_state': <state light.led_strip_3_1=off; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, supported_features=145, child_id=1, V_STATUS=off, device=mqtt, friendly_name=LED Strip 3 1, V_RGB=ff4328 @ 2017-05-14T23:52:37.597832+02:00>, 'new_state': <state light.led_strip_3_1=on; V_PERCENTAGE=15, description=, battery_level=0, node_id=3, max_mireds=500, child_id=1, rgb_color=[255, 67, 40], V_RGB=ff4328, V_STATUS=on, supported_features=145, device=mqtt, friendly_name=LED Strip 3 1, min_mireds=154, brightness=38 @ 2017-05-14T23:52:59.015262+02:00>, 'entity_id': 'light.led_strip_3_1'}, 'origin': 'LOCAL'}, 'type': 'event'}
2017-05-14 23:52:59 DEBUG (MainThread) [homeassistant.components.api] STREAM 140382427432640 WRITING data: {"time_fired": "2017-05-14T21:52:59.015318+00:00", "event_type": "state_changed", "data": {"old_state": {"attributes": {"supported_features": 145, "description": "", "V_STATUS": "off", "device": "mqtt", "battery_level": 0, "V_PERCENTAGE": "15", "child_id": 1, "friendly_name": "LED Strip 3 1", "node_id": 3, "V_RGB": "ff4328"}, "last_changed": "2017-05-14T21:52:37.597832+00:00", "last_updated": "2017-05-14T21:52:37.597832+00:00", "state": "off", "entity_id": "light.led_strip_3_1"}, "new_state": {"attributes": {"V_PERCENTAGE": "15", "description": "", "battery_level": 0, "node_id": 3, "max_mireds": 500, "child_id": 1, "rgb_color": [255, 67, 40], "min_mireds": 154, "V_STATUS": "on", "supported_features": 145, "device": "mqtt", "friendly_name": "LED Strip 3 1", "V_RGB": "ff4328", "brightness": 38}, "last_changed": "2017-05-14T21:52:59.015262+00:00", "last_updated": "2017-05-14T21:52:59.015262+00:00", "state": "on", "entity_id": "light.led_strip_3_1"}, "entity_id": "light.led_strip_3_1"}, "origin": "LOCAL"}
After restarting HA and retrying the same thing, it works as expected. See the log below, at 23:59:18 I click the switch in HA, which results in the message being sent via mysensors.gateway_mqtt:
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140579111531856: Received {'service_data': {'entity_id': 'light.led_strip_3_1'}, 'service': 'turn_on', 'id': 10, 'domain': 'homeassistant', 'type': 'call_service'}
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: service_call_id=140579955139080-1, service_data=entity_id=light.led_strip_3_1, service=turn_on, domain=homeassistant>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event call_service[L]: service_call_id=140579955139080-1, service_data=entity_id=light.led_strip_3_1, service=turn_on, domain=homeassistant>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.143323+00:00", "origin": "LOCAL", "event_type": "call_service", "data": {"service_call_id": "140579955139080-1", "service_data": {"entity_id": "light.led_strip_3_1"}, "service": "turn_on", "domain": "homeassistant"}}
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: service_call_id=140579955139080-2, service_data=entity_id=['light.led_strip_3_1'], service=turn_on, domain=light>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event call_service[L]: service_call_id=140579955139080-2, service_data=entity_id=['light.led_strip_3_1'], service=turn_on, domain=light>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.151214+00:00", "origin": "LOCAL", "event_type": "call_service", "data": {"service_call_id": "140579955139080-2", "service_data": {"entity_id": ["light.led_strip_3_1"]}, "service": "turn_on", "domain": "light"}}
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140579955139080-2>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event service_executed[L]: service_call_id=140579955139080-2>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.155779+00:00", "origin": "LOCAL", "event_type": "service_executed", "data": {"service_call_id": "140579955139080-2"}}
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140579955139080-1>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event service_executed[L]: service_call_id=140579955139080-1>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.159536+00:00", "origin": "LOCAL", "event_type": "service_executed", "data": {"service_call_id": "140579955139080-1"}}
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140579111531856: Sending {'success': True, 'result': None, 'id': 10, 'type': 'result'}
2017-05-14 23:59:18 DEBUG (Thread-13) [mysensors.gateway_mqtt] Publishing 3;1;1;0;2;1
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: service_call_id=140579955139080-3, service_data=payload=1, topic=mysensors-in/3/1/1/0/2, qos=0, retain=True, service=publish, domain=mqtt>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event call_service[L]: service_call_id=140579955139080-3, service_data=payload=1, topic=mysensors-in/3/1/1/0/2, qos=0, retain=True, service=publish, domain=mqtt>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.165609+00:00", "origin": "LOCAL", "event_type": "call_service", "data": {"service_call_id": "140579955139080-3", "service_data": {"payload": "1", "topic": "mysensors-in/3/1/1/0/2", "qos": 0, "retain": true}, "service": "publish", "domain": "mqtt"}}
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event service_executed[L]: service_call_id=140579955139080-3>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event service_executed[L]: service_call_id=140579955139080-3>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.170379+00:00", "origin": "LOCAL", "event_type": "service_executed", "data": {"service_call_id": "140579955139080-3"}}
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.mqtt] Received message on mysensors-out/3/1/1/0/2: 1
2017-05-14 23:59:18 DEBUG (Thread-1) [mysensors.gateway_mqtt] Receiving 3;1;1;0;2;1
2017-05-14 23:59:18 DEBUG (Thread-13) [homeassistant.components.mysensors] Update: node 3, child 1 sub_type 2
2017-05-14 23:59:18 DEBUG (Thread-7) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 40, value = ff4328
2017-05-14 23:59:18 DEBUG (Thread-7) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 2, value = 1
2017-05-14 23:59:18 DEBUG (Thread-7) [homeassistant.components.light.mysensors] LED Strip 3 1: value_type 3, value = 15
2017-05-14 23:59:18 INFO (MainThread) [homeassistant.core] Bus:Handling <Event state_changed[L]: old_state=<state light.led_strip_3_1=off; node_id=3, V_PERCENTAGE=15, description=, child_id=1, supported_features=145, battery_level=0, device=mqtt, V_STATUS=off, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:57:35.765794+02:00>, new_state=<state light.led_strip_3_1=on; node_id=3, V_PERCENTAGE=15, max_mireds=500, description=, min_mireds=154, child_id=1, supported_features=145, battery_level=0, rgb_color=[255, 67, 40], device=mqtt, V_STATUS=on, brightness=38, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:59:18.476789+02:00>, entity_id=light.led_strip_3_1>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 FORWARDING <Event state_changed[L]: old_state=<state light.led_strip_3_1=off; node_id=3, V_PERCENTAGE=15, description=, child_id=1, supported_features=145, battery_level=0, device=mqtt, V_STATUS=off, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:57:35.765794+02:00>, new_state=<state light.led_strip_3_1=on; node_id=3, V_PERCENTAGE=15, max_mireds=500, description=, min_mireds=154, child_id=1, supported_features=145, battery_level=0, rgb_color=[255, 67, 40], device=mqtt, V_STATUS=on, brightness=38, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:59:18.476789+02:00>, entity_id=light.led_strip_3_1>
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.websocket_api] WS 140579111531856: Sending {'event': {'time_fired': datetime.datetime(2017, 5, 14, 21, 59, 18, 476846, tzinfo=<UTC>), 'origin': 'LOCAL', 'event_type': 'state_changed', 'data': {'old_state': <state light.led_strip_3_1=off; node_id=3, V_PERCENTAGE=15, description=, child_id=1, supported_features=145, battery_level=0, device=mqtt, V_STATUS=off, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:57:35.765794+02:00>, 'new_state': <state light.led_strip_3_1=on; node_id=3, V_PERCENTAGE=15, max_mireds=500, description=, min_mireds=154, child_id=1, supported_features=145, battery_level=0, rgb_color=[255, 67, 40], device=mqtt, V_STATUS=on, brightness=38, V_RGB=ff4328, friendly_name=LED Strip 3 1 @ 2017-05-14T23:59:18.476789+02:00>, 'entity_id': 'light.led_strip_3_1'}}, 'id': 2, 'type': 'event'}
2017-05-14 23:59:18 DEBUG (MainThread) [homeassistant.components.api] STREAM 140580067735248 WRITING data: {"time_fired": "2017-05-14T21:59:18.476846+00:00", "origin": "LOCAL", "event_type": "state_changed", "data": {"old_state": {"last_updated": "2017-05-14T21:57:35.765794+00:00", "state": "off", "last_changed": "2017-05-14T21:57:35.765794+00:00", "attributes": {"battery_level": 0, "node_id": 3, "V_PERCENTAGE": "15", "device": "mqtt", "child_id": 1, "V_STATUS": "off", "description": "", "friendly_name": "LED Strip 3 1", "supported_features": 145, "V_RGB": "ff4328"}, "entity_id": "light.led_strip_3_1"}, "new_state": {"last_updated": "2017-05-14T21:59:18.476789+00:00", "state": "on", "last_changed": "2017-05-14T21:59:18.476789+00:00", "attributes": {"node_id": 3, "V_PERCENTAGE": "15", "max_mireds": 500, "description": "", "min_mireds": 154, "child_id": 1, "V_RGB": "ff4328", "battery_level": 0, "rgb_color": [255, 67, 40], "device": "mqtt", "V_STATUS": "on", "brightness": 38, "supported_features": 145, "friendly_name": "LED Strip 3 1"}, "entity_id": "light.led_strip_3_1"}, "entity_id": "light.led_strip_3_1"}}