Pipewire does not configure TeamSpeak 3 input channels correctly
In pavucontrol the volume slider for the microphone input keeps jumping back to 0. If the channels are unlocked you can see that the problem is the second channel for stereo input is forced to 0 because it is not connected to anything with my mono microphone. Moving one channel volume slider seems to affect the other one which creates bad behaviour.
When the same is tested under PulseAudio it is possible to move both sliders freely even though only the first one actually affects volume. 
Since this does not happen with mumble which seems to accept 3 channels and jack programs only show one channel for TeamSpeak (under PipeWire) my best guess is that PipeWire misconfigures TeamSpeak to be mono somehow.