But Flying Pig's suggestion makes sense. The program seems to test the victory conditions for the campaign at certain points during a turn, and if you have the "Short Game" box checked, those are the conditions it'll test against. I would then expect new victory conditions to be set, and they would be tested in due course, allowing the short-long-world victories to be creditted in due course.

It doesn't make sense to program an edge triggered victory condition "Have I gone from 14 to 15 provinces?", rather than a level triggered one "Have I at least 15 provinces?". So I doubt you'ld have to deliberately lose provinces, in order to fulfill long conditions later, after eliminating the short victory opposition faction(s). Thus most likely "simultaneous" victory conditions, would result in a sequence of victory popups perhaps 1 per faction turn (victories are achievable as a result of non-player faction action so conditions ought to be tested more often than at end of player turn only).