Mmm, I'm pretty sure that's not what desynch means.
I don't play PvP, but AFAIK thats where desynch is a very real aspect of the game. Basicly what it means is that the player is not where he seems to be on other players minimap, or that he might be right next to you, but you wouldn't see him in your computer. I think it's caused by very fast movement or something like that(pala charging with vigor aura on etc).
I'm sure somebody with more information on this can explain a little better.