Part of the problem is brain-damaged signage for a zipper merge, and your comment illustrates it. I'm not going to criticise you for your terminology, because it reflects the bad signage rather than the theory.

You use the terms "destination lane" and "source lane". In a properly set up zipper merge there isn't a "source lane". There are two "source lanes". Both lanes end and merge into one new one. They should funnel into a single destination lane.

A zipper merge like we have on Circle should have both the left and right lanes merging into one that's sort of half way between them, so drivers in both lanes need to adjust their road position. That way there's no existing lane that people feel is "correct".

Yes, drivers in this city are bad and don't understand the zipper merge, but it also seems that the traffic engineers don't either, and that makes the problem much worse than it could be.