Glitchy Clip in Premier Pro

Hello Everyone,

I am working on edditing some drone footage I have compiled in Premier Pro.  I have 3 clips, trimmed, edited, and so on.  Two clips were shot in 5.1k 30fps, the third is in 4k 30fps.  When everything was imported, all three clips played fine.  When I went to export the clip, the 4k clip was sized differently (had big black bars around it in my video player) and was jumpy, it would play a few seconds then freeze, but the audio track continued playing.  I went back to Premier Pro and it did the same thing in both the preview and the export preview.  I am assuming I clicked something and messed up the file but I have no idea.  The original still plays fine, even in premier pro.

Any ideas on where to start?  I could probably dump the project and start over, but I don't want to waste that time and I would like to try and learn from my mistake here.

Also, what are recommended export settings for best quality?  I am shooting in Apple Pro Res 244HQ and editing on Windows.

Thanks!