Do the videos play outside of Premiere?
Here is a thread with someone who reported a similar problem:
Premiere not importing mov files.
The solution above was installing:
Yes, I can watch the videos in VLC and Quicktime.
What is the origin of this file?
If it is a screen capture run in through Handbrake, set it to constant framerate and try again.
These files come from external recordings, are captured on SSD but are always transported to the computer for editing. In the previous versions they opened normally.
I recommend uninstalling QuickTime. You don't actually need it.