That's not really the type of "skipping" that is the issue. Software tends to ask the system the current time (via a library), and the system responds with a "

That's not really the type of "skipping" that is the issue. Software tends to ask the system the current time (via a library), and the system responds with a "here is a number, it is the number of [units] since [epoch]". The library then converts that number using a formula to work out a date/time. If it is decided a leap second is added or subtracted, and the library's formula doesn't account for it, then the time will be calculated incorrectly. For most software it is unlikely to matter too much, but this sort of thing can lead to unpredictable emergent behavior in complex networked systems.