Can you check if you have Sound Recognition enabled in Accessibility? Some folks are reporting turning this off resolves the issue (sounds unlikely, but worth a shot).
This is how I resolved the issue myself:
I had a system wide issue with AirPods and my iPhone, they would show as connected at the system level, but none of the apps could use them for playback/calls. I tried re-pairing/forgetting/restoring AirPods to defaults, then a full erase and restore from backup....nothing fixed it. I then did a full erase, didn't restore from backup and it worked fine, I've since manually re-installed everything and for me everything is still working. So it was something in my config, rather than the raw beta code.