Inner bearing races and outer bearing races are made from hard brittle material and can easily be cracked with a moderate blow from a hammer or dropping it or whatever. I have seen mechanics remove (industrial) bearings faster than anyone using the best pullers , he would place a rag over the bearing (to prevent flying fragments) , carefully position a dull punch or chisel on the race , then deliver a careful moderate blow with a hammer and the bearing would crack.
That is why I was surprised to see the outer race incorporated into the gear on the EC225 , I always thought gear teeth should be less brittle and the bearing should have its own outer race pressed in. Reading the fine print it sounds like they use different hardening for the inside of the gear (race) so obviously they have figured out a way to make it work and are obviously much more knowledgeable than I am
Mostly I wanted to point out that impact damage or shipping damage has some merit in this discussion. Actually I think it would most likely happen pre-installation , the gear was dropped or impacted in some way to start a microscopic crack
I repeat my surprise while watching a (careful) mechanic disintegrate a bearing race with a light hammer blow , it breaks like glass , pieces fly all over the place.