There might be a clue in the Harmony fix to web sockets: [Resolved] Harmony Hub issues after February 2019 update v.4.15.250
It appears there was a change to the websockets api in .88.
2019-02-22 09:06:24 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.1877008272] Error handling message: {‘type’: ‘call_service’, ‘domain’: ‘alarm_control_panel’, ‘service’: ‘alarm_arm_night’, ‘service_data’: {}, ‘id’: 18}
I confirmed this works with the HA Manual alarm: https://www.home-assistant.io/components/alarm_control_panel.manual/
The issue only affects envisalink.
Just FYI, still in 88.2
Thanks!