At least in the CFMs, I have seen the results of ice shedding from the fan blades and spinner. It completely destroys the inner acoustic panels surrounding the fan.
I have never seen any sort of bad cowl ice, but I am sure a massive hunk of it going through the core wouldn't be good.

This whole thing is a whatever from me. Already over 1,500 max airplanes flying around with the exact same issue. They shouldn't hold up certification for the same issue that hundreds of thousands of folks are already flying around with.