Another 20 calls later, the BT recording crashing has been identified and fixed...
Cause and resolution for archival purpose: The moment BT hangs up, the pulseaudio source hw1 disappears from underneath GStreamer, causing it to spit a critical error. My solution is to just stop the recording as fast as possible (and not in the proper, slightly slower way it was done before).

Can a mod merge this thread? Thanks