Hello Holger Bunkradt,
Thanks for reaching out to Microsoft Community. I'm sorry to hear about this issue on your replacement dongle and Surface headphones. I understand how concerning it is to have such problem.
In this case, please try resetting the firmware on your headphones first. Here's how to reset the firmware:
- Plug the USB cable into your Windows 10/11 PC or into a USB power adapter (not included) for a wall outlet.
- Press and hold the power button on your headphones.
- While still holding down the power button, connect the USB-C end to your headphones.
- Release the power button.
Then, ensure that the Surface app is updated by getting updates from the Microsoft Store app. See Get updates for apps and games in Microsoft Store.
Let me know how it goes.
I'll wait for your response.
Kind regards,
StevenK