Can I use my Bluetooth headset as a microphone?
From the Sound Preferences menu we select the Input tab to choose our Bluetooth device (here depicted for a Philips headset) for audio input:
In order to use your headset for telephony we will also have to make sure, that the hardware is set to Duplex mode in Hardware -> Settings:
Note: In duplex mode the sound quality may not be very high due to usage of the HSP/HFP codecs.
I have no explicit solution but the bug ticket for this: #508522
Perhaps sometimes there will be the solution for this issue.