I’m not sure how to 100% replicate this bug, but I do know it has something to do with stopping the current playtest while in first person. This is what happens:
https://i.gyazo.com/ab6f561bf05523a5c62bdd4abe10b8e9.mp4
The camera properties are default, not modified by any plugin or script, and this happens in several different games. Even when disabling all of my plugins or scripts it can happen. This is in a new baseplate with no plugins or scripts besides the default roblox scripts.
https://i.gyazo.com/7edf9f238a02e1f295ac5ecfd1f79b88.mp4
I was playing around and this is what happens when changing the camera subject: