Clips freezing. I deleted media cache, tried Software Encoder. Clips play fine on PC

I'm really looking for some advice here.  PC is pretty beefy. Its an 13900k with an RTX 3080GPU.  NVMe drives. 64GB ram.  

I've imported some Mavic 3 10bit H265 60fps video's which play absolutely fine on the pc, as well as some Sony A7S3 H265 10bit 4.2.0 footage.. The sequence is 29.97, i as i always do, interpret footage to 29.97fps. to match the sequence. Anyway on a few clips, it just freezes. I'm lost on what to do. It seems to be on the mavic clips   

So far, i've restarted the computer

I've deleted the media cache

I've tried exporting using the Software Encoder as apose to using the hardware encoding of the GPU. 

I've even deleted the clips it freezes on and re-imported them back into Premiere and replaced them with the newly imported clips. But its just freezes.  

I'm supposed to deliver this paid project tomorrow, and i'm completely stuck.  

The only thing i did which was different from what i normally do is used is i sent the audio track to Adobe Audition to shorten it. But really this is nothing that i don't normally do.   This machine is a new fresh clean build of Win11 (latest nVidia drivers) everything up to date.  This is only my 2nd video i've created on this new build.  The first went without hiccup.  Despite having a great spec machine, i still convert my clips to proxy, just because i like everything to go smooth.   I'm not sure what else to try. 

Any advice would be warmly appreciated.