Oh my god! Thats brutal! I have the same MTX but I haven't seen anything like that. I have lost only 2 nipples when I had a double track, but it was my fault... the dealer are foult between the nipples when I landed, and its came apart :S
It's the nipples, fuckin' dumbasses think that they can use alloy nipples on disc brake wheels, such is not the case. Make sure they re-lace it with brass nipples next time.