iMovie for iPhone audio out of sync.

I’m using an iPhone 14 Pro on IOS 26.2 and I’m trying to make a video with iMovie which is running

version 3.0.5 (5815.58.34)

My project is finished and I wanted to review it before I save it and eventually upload it. When I watch the video back within the edit, everything plays perfectly, all the audio is synchronised and the video plays as intended.

However when I watch it back full screen by pressing the play button outside of the edit (pictured and circled) then the audio goes out of sync at the same point in the video every time. (Also pictured. White line is the point at which audio goes out of sync.

to be clear, I haven’t detached the audio from this clip, the audio is part of the video clip if that makes sense.

I’ve tried detaching audio, nothing I’ve tried deleting that clip and re adding/cropping it, I’ve tried detaching audio and moving it around to see if I can get lucky, I’ve tried removing filters, but nothing I’ve tried has worked even a little bit and it’s extremely frustrating.

any help would be massively appreciated.