The problem frequently crops up in order-deterministic systems that use time and haven't accounted for the edge case of all the vagaries related to time-keeping of this being only one.

I've worked on some extremely sensitive systems that had thousands of lines of C dedicated to handling skewing a time gap across an hour-per-second when necessary. I know that code assumed only "missing" time (jump-forwards)... Even knowing what I know as a developer now, if I was re-implementing that system from scratch and didn't have this top-of-mind, I'd bet I would miss "overlapping" or "duplicate" time entirely.

Maybe that is more of a me problem than others, but I'd bet there are some safety critical systems out there where the responsible engineers, QA, and specs all missed this as well.