Problem with some clips not recognised by PP

Hi guys,
I've got an a7Siii.
I also edit in PP.
I have the latest version.

When I'm covering events, I do stills and vids.

Where possible, I will switch between Manual (for stills) and a saved settings mode (for video, 4K).
Sometimes due to time constraints during an event, I'll simply film a clip or few in Manual.

When I import the clips into the new project in PP, I get low level incurrence warnings and notice the clips filmed in Manual mode aren't recognised by PP.
For this reason, I can't create proxies of those clips either.

I have compared the properties of the clips filmed from a dedicated setting and the clips filmed in M mode and can't see any discernable differences.

Can anyone shed any light on this issue?
Thanks!