Broken airlock?

The 3 piece airlock that came with my kit has a crack! From what I can tell, it's not leaking at all... I am assuming that this happened when I was trying to pull the blow off tube off the airlock..... Is this fairly common? It would seem that the design of the airlock is fragile enough that I could see this happening again fairly easily in the future..., wondering how many extras I should order.

I keep 4 on hand. Haven't used the 3 piece. But at a dollar each, buy a handful.