The only change I’ve noticed lately is that the game automatically enters vanity mode when standing still (Rotatable Stationary Camera), but that doesn’t do what you’re describing. I noticed that there’s a dropdown box in Settings under Gameplay for “Controller Style Movement”, but I don’t notice any difference between the options when using mouse & keyboard in either the 3rd person or 1st person views.
What you’re describing actually sounds like either an accessibility feature like Center View and/or Auto Slope from older Unreal games.
Can you confirm if you’re using Mouse & Keyboard or Controller, and whether you’re seeing this in 1st person, 3rd person, or both? Also, have you made any changes directly to the ini files? If so, you might want to try renaming them and letting new ini files get generated to see if that fixes things.
EDIT: Lastly, is it possible you’re activating target lock? I always unbind it myself, but occasionally it gets activated and then I find my camera doing odd things.