I’ve noticed for a while that when playing a linked video directly in the app, it doesn’t respect the global auto-rotate setting of the screen. Only today did I notice that there’s a “lock rotation” button at the top of the player, but unless I’m misunderstanding something, it seems to do the opposite of that it’s showing: when I see the little lock it’s unlocked, and then it’s just the rotation icon it’s actually locked. For context, my phone’s rotation is always locked, but the video always rotates on me.

In general my suggestion for the behavior for playing video would be to rotate and lock it to the “correct” orientation for it’s aspect ratio. It makes no sense to play a portrait video in landscape, neither does the other way around. Rotating the phone should probably still be able to flip it 180°.