Cannot get ChatGPT to use my bluetooth headset for discussion

Why is the ChatGPT app not using my bluetooth headset?

I want my bluetooth headset on Android, that normally works with all apps, to also work with chatgpt in voice chat mode. However when i connect it chatgpt briefly plays a sound in the headphones while connecting to voice chat and then defaults to phone ear speaker, not even the normal phone loudspeaker, let alone the headset.

It does not seem to use the microphone on the headset either.

I have tried allowing and disallowing to use the headset for phone calls, turned on and off media capability but does not seem to matter.

Is this supposed to work? If so - How? If not - Why not?