That's a sweet group! Strange how things happen like those splits. I can't tell from the photo but guessing the split is right in the side of the case, long ways? If so I would guess bad brass. But what are the chances those two would get fired first?
I was REALLY perplexed. The splits are very hard to see in the pics, but yes they are long on the sides. If you look closely, it looks like a black dot at the ends of the splits on both cases. Not a single one since, Fingers crossed.