Diagonal lines - proxies - all kinds of trouble

Hi everyone, So I have been having a strange issue in Premiere. I recorded 7 talks with two camera angles. I proxied on ingest all footage. These were then worked on from google drive (In the process of changing this workflow as it is temperamental)

Currently one camera angle in one of the talks is showing all of it to have diagonal lines. I can see the original media at the correct file size as well as the proxy in the project folder in file explorer - so everything is there. I thought, no problem, I will just replace with clip from bin and it will fix this. The clip is 38 minutes long and the RAW is 13.4gb and the proxy is around 2.3gb. However in Premiere (even if I re-import the original file) it says the duration is 1.7 seconds long. 

I have tried making the clips(s) offline and replacing clip from bin but as it's only 1.7 seconds long it obviously doesn't work. I can import the proxy direct from file explorer and that shows the correct length but obviously I want the original media to be linked to it for when I render. 

I am so confused. Has anyone had an issue like this before? The entire rest of the project is fine and all the other talks with second camera angles are all fine, just this one clip. 

Many thanks