Trying out the new alpha-release for Android I've mostly had issues with audio output. I'm trying to use Bluetooth headphones and I frequently have to restart the game for them to work. I've occasionally gotten the "rejoin world to switch outputs" message but not consistently.
My guess is that the Bluetooth headphones have a transient connection issue and that breaks the game's connection with them without triggering the output device switch message. I hope that rejoining worlds when you switch output devices is a temporary workaround for some internal issue and fixing that will probably fix my issue as well.