I have a brand new iphone 15pro max and I'm having this exact issue on clips at 24fps.
1TB SSD on mine. I couldn't get the phone to record a clip in cinematic mode at 4k 24fps without the end result being choppy/glitchy... then ultimately, corrupt and unable to playback.
No rhyme or reason as to why. I have some clips that are fine.
When trying to recreate the issue, I realized that I would have to close the camera app and reopen. Then, recording will work for the first clip. BUT, once I cut, then record a 2nd clip, everything after that is corrupt.
Right now, I can only record one clip before having to close the app and reopen to roll again.
Would love some answers from Apple. asap.