Used it to resize/decap maybe 200-225 cases. I have never had this happen and not sure what the cause would be.
It worked just fine for all the previous ones so it bottoming out I don’t think could of been the problem.
Other than the part being defective to begin with, "bottoming out" could still be your problem.
Very drastic bottoming out can break it right then. But less severe impact, that you won't even feel in the press handle, will cause stress on the threaded parts, and can even bend the shaft, over time. The shaft should be adjusted so the stem never contacts the case web at all. Decapping pins are long enough to push out the fired primer without the stem touching the case. (if they aren't you need longer pins).
Most die makers are really good about sending replacement parts often at no charge. Contact your die maker and tell them what happened. Odds are they'll send you new parts.
Another possibility, is that the button was simply not fully screwed on the shaft, and possibly bottoming out because of that. Or even if not bottoming out being loose could cause enough "wobble" to crack the part.
Get the replacement, snug everything up, make sure the shaft isn't too far "down" and go back to loading. Things should be ok.
I don't load for "speed" (number of rounds per hour) and some years ago gave up on progressive presses, not only going back to a single stage press, but going to hand depriming, using the nearly unbreakable Lee punch and base set. I do it in batches, and might spend a day doing nothing but depriming my brass (several calibers) using that set. also gives me the emotional release of hitting something with a hammer, and feeling good about it.