HmIP-BSM becomes unresponsive when triggered by automation

Working on my first proper HA installation, starting with a simple automation:

I’d like to turn on a Homematic HmIP-BSM switch triggered by an IKEA Vallhorn motion sensor. However, when the automation is run the switch does not turn on and instead the whole device becomes unresponsive and I’m getting a System Message in the CCU3:

Device communication disturbed

After a few more elaborate attempts (including more conditions etc.) I have stripped the automation down to the basics (or so it seems to me anyway):

- id: '…'
  alias: 1. Entrance Light on Motion
  description: ''
  triggers:
  - entity_id: binary_sensor.1_entrance_sensor_motion_occupancy
    from: 'off'
    to: 'on'
    trigger: state
  actions:
  - alias: Turn on the light
    action: switch.turn_on
    target:
      device_id: …
    data: {}
  - alias: Wait until there is no motion from device
    wait_for_trigger:
      entity_id: binary_sensor.1_entrance_sensor_motion_occupancy
      from: 'on'
      to: 'off'
      trigger: state
  - alias: Wait the number of seconds that has been set
    delay: 120
  - alias: Turn off the light
    action: switch.turn_off
    target:
      device_id: …
    data: {}
  mode: restart
  max_exceeded: silent

When I trigger the switch from the HA UI it works fine.
After turning it on/off manually the switch will come back and be available again.

As a newbie it feels like I’m missing something obvious. Grateful for any suggestions.

Both — HA and CCU — are on the latest software version.
The CCU and the HA on RPI + ZHA dongle are right next to each other, physically, but the ZHA dongle is properly set up using a cable between the device and the RPI.

EDIT: Did some more testing. Other switches of the same type seem to work as expected. Which made me believe it might be a range issue. This particular switch is as far from the CCU as possible in the house. That being said, If I trigger the switch from Home Assistant UI directly it (most of the time?) works fine.