Sorry if this is obvious, maybe this will help someone. Was getting confused why my level sequencer camera angle was really off in standalone/new window full screen mode (my Level Sequencer render crashes every time on 4.16 so I am resorting to ShadowPlay). Ultrawide monitor when playing in standalone/new window causes FOV to change, so you will miss things in the Level Sequencer (things that are meant to be on camera may be off). Pressing F11 and shrinking the screen down to regular 4K with black border on left/right fixes it.
I guess most games don’t support ultrawide. Sorry if this was super obvious, maybe this will help someone who is scratching their head why all their hardwork on camera angles are messed up when going full screen on ultrawide.
Figured out my problem from another thread I created, so trying to delete that one and keep this one on the small chance that someone searches for same issue.