This is a real bug IMO. There are several unresolved discussions here on this.
There are 4 situations where you can see audio: Live stream, playback, save of playback, and the 12-second cloud clip. In my experience, only the cloud clip is normally in sync, or close to it. I have been able to get a saved playback clip to be in sync (or close to it), but the only way I’ve been able to do that is save the clip several times (regardless of whether or not it is in sync on playback), and then see which of the saves is the closest. It varies.
I’d love to hear if anyone DOESN’T have this issue in any of above 4 situations.
Here is a post I made on the subject with an example. I started this thread last May, and have recently re-verified as recently as 5 days ago with new footage on a 2018 iPad: