I also assume it's the backdoor but with this piece of info (there is a "safe" state") the Intel people cannot legally claim they didn't know it was unsafe, so

I also assume it's the backdoor but with this piece of info (there is a "safe" state") the Intel people cannot legally claim they didn't know it was unsafe, so stupidity is ruled out (as in the saying never attribute to malevolence ...) The last missing piece is now whether ME was actively put there to enable a few agencies to gain unauthorized access.