While I'm not sold on the idea that a modern striker fired gun should need a break-in, they do say to expect a 200 round break in for the big guns.
In the example of one dr920 i have access to, it held true. A few feeding issues during that period that alleviated after.
I imagine that carries over to the small guns as well, so i would expect some failures early. I still don't like it but SS seems to expect it.