After some digging, it seems this deadlock is related to something in my positional audio update code, and possibly FMOD. The more sounds I have the more quickly it will deadlock.
My guess would be as a result of many calls to sound.status(), sound.set3dAttributes(), or sound.setVolume(), but who knows.
I’ll try to isolate the sound code and see if it still has a problem on its own. That should make a fairly good demo of the problem.