playback glitch in timeline but not in export

Hoping someone can help me out. I'm getting this glitch/flash during playback of my timeine, however it does not appear on my exports. See pic. I've tried switching the in renderer in project settings to mercury playback - software only, and also tried resetting prefrences. Also see pic of my timeline settings. appreciate any insight!

running premire 2023 on macbook M1 max