Yeah, just confirmed it, completed all my leathercraft guildleves, only 3 guildleves remaining for local guildleves, I've only done the 5 leathercrafting ones since the guildleve timer reset and it won't let me accept more.
So basically, if you accidentally take a guildleve for the wrong craft, for example you're a armorer and accidentally take a blacksmith guildleve you are stuck with it till the 36 hour guildleve reset. Even if you haven't done it or started it, just by accepting it you are bound to it. Kind of sucks, especially when they've not been done.
Long Live Vana Diel.