Hi, @CraigC. We are working to put in some safeguards to prevent out of data clients from causing this. Now, I don’t know for certain if that is what caused this issue in your case but, if so, we are working on a fix to return errors to Git clients using an out of Git LFS version to talk to Large Media.
About the file which cannot be transformed, it turns out it is more complicated to fix than I realized. Would it be possible to change the filename and upload it again? Also, the image itself must be modified in same way that changes the file checksum when this is done. (So, new name and new checksum - both.)
I realize that might not be possible though. If it is not, please let us know and I’ll see about fixing this “the hard way”.