Failure to pair Ikea Somrig (ZHA, Sonoff stick) with exception in discover log

Hello,
I’m trying to pair an Ikea Somrig remote with my ZHA integration (Home assistant container 2025.9.1, Sonoff stick with firmware 20250321). Reading several similar forum entries doesn’t help: I can put the remote into pairing mode (pressing 4x the inner button not too fast), then the add dialog in HA finds the device but it’s stuck at “Interview complete\nConfiguring” even if I keep pushing one of the normal buttons on the device at ~ 1 Hz and the device isn’t added to the list of devices.

Looking at the logs I see an exception there:

Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/zigpy_znp/zigbee/application.py", line 924, in send_packet
    await self._send_request_raw(
    ...<11 lines>...
    )
  File "/usr/local/lib/python3.13/site-packages/zigpy_znp/zigbee/application.py", line 838, in _send_request_raw
    raise InvalidCommandResponse(
    ...<2 lines>...
    )
zigpy_znp.exceptions.InvalidCommandResponse: Unsuccessful request status code: <Status.NWK_NO_ROUTE: 205>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/zigpy/application.py", line 884, in request
    await self.send_packet(
    ...<14 lines>...
    )
  File "/usr/local/lib/python3.13/site-packages/zigpy_znp/zigbee/application.py", line 982, in send_packet
    await self._discover_route(device.nwk)
                               ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'nwk'

that is repeated several times which makes me believe that my problem is different from the threads I found during my research. I also confirmed that the quirk that is the result of at least one older thread is already part of my installation. Any help welcome!

I tried to pair the device today again (with the plan to look at the debug logs in more detail to maybe understand what’s going wrong) and it paired without issues. The only thing that is different than before is that Home assistant is at version 2025.11.1 now.