Hello Pirmin,
Unfortunately I do not get any output on the headphones.
I never had tested audio on this device with previous releases.
You can enable reporting in the audio launcher by setting the 'report_mixer' attribute (the launcher currently contains the wrong attribute) and watch the '/report/runtime/audio/mixer_state' report while (un-)plugging your headphones.
We already had to add quirks for other systems in the past to the driver where it did not identify the widgets properly. That could be the case here as well.
Regards Josef