I'm that other guy :-)
I didn't see your question - sorry about that.
I've seen quite a few threads regarding split cases, and it seems to be a commen thing, happening in all brands of firearms. Some think it is because the cases aren't annealed after necking.
A guy here in Denmark shot a box without a single crack. Next time out, nearly every third or fourth case cracked. Same lot.
The ones I had, all had cracks roughly 3mm long - 1/8" long