Did your crusade marker return? If yes, then you will never keep the men you had in that crusade. They are scattered into the winds. You just happened to get fooled by the Hungarians to pay for them before the crusade dissolved (And that is really a glitch, I think, but live and learn and I'm sure you won't get fooled twice that way).
If the crusade marker didn't return, then you have indeed discovered a more bugged way to lose men
Never happened to me before though, which isn't saying a lot really.