The part replacement isn't being blocked? The OP's CM5 with replaced RAM is still a working CM5 according to him. And fully functional compared to before the replacement.
"Each chip is programmed with the timing settings and storage size settings of just the RAM we ship it with, and doesn't know how to boot with anything else." I don't know if you could call that "blocking." I mean you could call it that but I don't know if that's legally what it would be.
So European institution following this discussion would be wise to ASAP formally request RP Foundation to describe it either as a blocking security mechanism, or just a compatibility issue.
Between current inaction and eventual action, it settles the position of RP foundation, so they can't switch back and forth between "these people are circumventing security" vs "its just an unintended incompatibility", as long as they don't reveal their position its neither here nor there.