Yes, the A frame set to 00:00:00:00.
I’m pretty sure the problem is that the version of MediaComposer is so old (12.1.1) that the Film Settings tab hasn’t yet to be updated to include 24P Advanced Pulldown as an option. As a result, the pullin is set A for the first clip, but fails to count properly and messes up every clip afterward.
Hopefully I’m mistaken, and it can get fixed because digitizing this many tapes with this method is way too slow.