For example I'm having a problem that comes and goes now and then where Bluetooth audio is 300 ms delayed compared to the video playback everywhere except in Youtube on Safari, very strange. It's good for a few months then suddenly it becomes unusable, then back to zero sync delay after a few months.
I was thinking this might be related to CODEC selections etc or some hidden setting that might get changed which we normally aren't allowed to determine :)
(btw I know there is a difference between latency and synchronization - latency might be unavoidable but video sync should always be able to compensate - I got curious on how exactly that works, where in the app / SDK / OS pipeline does the a/v sync happen on a Mac?)