pmclaine,
As I understand it. suppressed AR's are typically over gassed to begin with, and the addition of a suppressor is raising the gas pressures enough to cause fracture of the BCG over time (never mind the additional cleaning required for the current gas operated M-4's). Something about the raising of the gas pressure causing the bcg to travel faster than designed, causing the bcg or cam pin to fracture prematurely.
It's been awhile since I read up on their stuff, but these were the guys that initially produced the "baffleless" suppressor design.
https://osssuppressors.com/
I'm pretty sure this is what I saw on some of the Marines' rifles a couple months ago...