Hi Matthias,
Works for me with my Siedle BTS 850-02. I had no issues during the setup. Although, as initially my bridge was dead-on-arrival, I had to keep my phone close to the Nuki Opener and run up and downstairs for each of the steps, ensuring that my phone doesn’t loose the Bluetooth connection to the Opener. This may be worth a try.
I’d definitely suggest that you check your wiring again. Also one thing to watch out for, there is a change in the suggested wiring: Known compatibility issues
disconnect the red Opener cable from the screw terminal of your intercom and put it in the clamp together with the yellow one.
I think this is most likely unrelated to the issue you’re facing, but worth a try. This is how my system is connected currently.
Generally for me, triggering the door opener was never an issue. Only the combination of Ring-to-Open and doorbell surpression has been giving me troubles, but they have already worked out somehwat of a solution for the doorbell surpression which is available in a beta version of the Nuki App.
Hope this helps.