From Jerry's post on Penny Arcade:
"You know how when you save your game, and a message comes up that says “Don’t Remove The Memory Card”? Well, if you are playing Precipice on an old Xbox with an MU and you decide to pull it out literally as you are saving the game, it will apparently crash. We thought we had accounted for that exact scenario but apparently our failsafes against timed MU pulls were not as tight as we had thought, so it failed Community Peer Review. That’s why it’s not coming out on the same day as the PC version, which manifests in all its glory on the 25th. We can’t resubmit for another seven days, so we (and you, if you want to play it on there) are in kind of a holding pattern. Zeboyd will push another build out on Tuesday; I’ll keep you posted."
We're sorry for the inconvenience for people who wanted to buy the XBLIG version. And keep in mind that this is just the XBLIG version - the PC version works fine and is still coming out on June 25th (5 more days!).