Striped Clips of Death without reason

Hello I am a Post Supervisor and Assistant Editor and my team has just ran into a truely perplexing issue that I am completely stumped by. We seem to have issues with clips from a certain shooting day, where our lead editor is getting the famous "stripes of death" on almost all the video clips (and sound clips, which are not linked to the video clips), from this one shooting day. the other clips from other shooting days are so far fine. 

 Even weirder, the clips that he pulled from (the original daymaster sequence) are totally fine. 

When I look at the clips in his sequence it seems they have a completely incorrect TC now from the master clips in the other Daymaster Project, which is strange as nothing was changed to these clips in his sequence. 

So far I have tried almost every work around I've heard of (media cache, relinking media, creating a new path for the media, find bin replace clip etc.) to no avail. 

Does anyone have any ideas? 

At the moment I am resigned to rebuilding this offending daymaster sequence from scratch and replacing those clips in his edit manually, but it would helpful to know what could have possibly caused this problem in the first place as this is a quite serious issue. 

Thank you!

Theo