I believe more work needs to be done from Autel's end on this problem. Your issue is not isolated and simply a case of one bad apple in the bunch. I've heard numerous concerns expressed over the gimbal in one form or another on this forum, and you can include me in that group. Despite all my attempts at calibrating, on average I typically start off a flight with a gimbal roll adjustment somewhere between 1.8 and 3 degrees. But even then, when flying sideways, that will typically cause the horizon to tilt and even spinning the aircraft will cause tilt issues. Under those circumstances when brought back to a hover it typically recovers, but slowly.
I fix all of it in my post production, but it doesn't help those people who rightfully want to take their video straight out of the drone and enjoy it.