Help. selfie video goes in and out of focus.

I'm trying to record a video. I have tapped the screen to lock the focus. It works for two seconds, and then it goes out of focus. I had an 11 pro for many years and I've never had a single issue with the focus going in and out. currently using iOS 18.7.1

This happens on both the camera app and tiktok. Really frustrating. Is there a known issue or a fix?