When importing screen capture video of Macbook Pro, there is visible distortion on clip in editor

Hello!

I recently started practicing Premiere Pro after using FCPX for a while.

I immediately noticed that when importing large MOV files generated by macOS screen capture, I see annoying visible distortion in editor view occasionally on random parts of the clip.

When I render the video the issue is not visible on the exported media file.

Question #1: Is this something that I can try to fix somehow?

Question 2: Can I always trust Premiere that my original footage is not touched when I see distortion on edit mode before rendering?

I'm using MacBook Pro 16 (AMD Radeon Pro 5500M 8 GB) with latest macOS version.