Screen Corruption / Distortion on Export

Hi, I've scoured the forums for anyone with this same issue but can't find anything, maybe I'm using the wrong terminology. I have an issue with a video I made where when I export it, at certain points in the video the screen pixelates and it inserts some pixels from a previous scene in the video (I've attached a screen cap). I had this same issue with iMovie and couldn't find a solution so thought I'd try again with FCP. The glitches are in different places in FCP but still there. I can export 10 times and they will always be in the same place which seems strange to me. It's very frustrating and would appreciate any ideas people might have as to the problem. I'm working from a 2017 MacBook Pro i5. Thanks in advance.

Try optimizing your media.

furneach wrote: ... I can export 10 times and they will always be in the same place which seems strange to me...

Disable background rendering in FCPX preferences, delete all generated library files, select all clips in the timeline via CMD+A, then do a one-time render with CTRL+R. Play the timeline to verify it looks OK. If it does, then export using these settings:

File>Share>Master File>Settings, Format: Computer, H.264 Faster Encode, Resolution: 1080p.

If it still happens, then make a snapshot copy of the project, open that and delete all effects with Edit>Remove Effects. Render that as above, then export using the above settings and see if it still happens. If it does not it could be an effect.

If it still happens, state the FCPX version and also the exact codec parameters of the material you are editing. You can play a clip in Quicktime Player and do CMD+I. Post that info, plus tell us what camera.