Readers here probably lack history, but I think this is the continuation of a somewhat-misplaced discussion where I advised against using the same paths on two drives, as it opens the way to oddly confusing errors. Multiple accounts were also described there, although I still don’t fully understand why that’s an advantage.
Looking closely at the errors (which might be in the post just below the red box) would find a file with a date, leading one to know which files are extra. They might even be leftovers never deleted from prior drive uses, however errors should have shown up in the first week job on the first week drive. If that drive was put away exactly as intended, and never touched by the second week job, I don’t see why it would start on this error, however if drives got confused and this was the second week drive, I’d expect such errors about extra files.
Close checking of file dates on the drives against backup dates in the two jobs might help find the problem.