This is a known issue. Marmarta mentioned the exact issue during the latest Qubes OS 2025 summit.
The happens because of the mute/volume-up/volume-down buttons on the headphone. There could be a USB hub/bridge in the headphone. And one or more devices attached to it. As an example. a class-complaint audio device and a virtual HID keyboard to send the ANSI codes for the mentioned buttons to the PC.