Who installed the centre diff bushings and the pins?
I can tell you from fitting mine that they can be tight if not installed correctly. Don't see a reason why the centre pin would snap like that other than incorrect install, as the pin merely allows the planetaries to turn and lubricates the bushings / planetaries.
At least the good thing to know is that the cryo treated parts have held up
Still no car..... turns out the extension housing on mine is different to the freakin donor box so another one is on the way.....no extra $ but delay nonetheless....