Zigbee2mqtt switch not responding in script

I have a strange issue in one of my packages.

Background:

The switch is a Tradfri E1603 control outlet connected through Zigbee2mqtt.

Both the Zigbee2mqqt controller and the application are updated to the latest versions recently.

In my package I have this:

sensor:
  ## Media center operations, sensor (Tradfri via Zigbee2MQTT)
  - platform: "mqtt"
    name: tradfri_media_switch
    state_topic: "zigbee2mqtt/tradfri_media_switch"
    availability_topic: "zigbee2mqtt/bridge/state"
    unit_of_measurement: "-"
    value_template: "{{ value_json.linkquality }}"   

switch:
  ## Media center operations, switch (Tradfri via Zigbee2MQTT)
  # used for powering up all media devices
  - platform: "mqtt"
    name: tradfri_media_switch
    state_topic: "zigbee2mqtt/tradfri_media_switch"
    availability_topic: "zigbee2mqtt/bridge/state"
    payload_off: "OFF"
    payload_on: "ON"
    value_template: "{{ value_json.state }}"
    command_topic: "zigbee2mqtt/tradfri_media_switch/set"

The script looks like this:

script:
  ## Script for setting up media when main media switch is still off
  media_from_off:
    alias: Media start als media switch uit
    sequence:
      - service: timer.start
        data:
          entity_id: timer.media_center_delay
      - service: homeassistant.turn_on
        entity_id: switch.tradfri_media_switch 
      - delay: '00:00:30'

When the script runs, the switch is not set.

Any tips where the error is (if any)?

Notes:
Manually changing the switch works flawless.
A second tradfri E1603 works perfect in automations and scripts.

UPDATE (20190517): Apperantly the automations and scrips in the bases are working fine. However Hass sometimes does not update the device. I also see this with the second Tradfri. Some times it does not switch and Hass also keeps showing the previous state.

Thanks for the help

Ralph