It appears that the Medical System Expansion 2 mod resolves the issue with archotech limbs not keeping track of the sub-parts of the limb (Hands and feet and such).

Medical System Expansion 2:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2056706586

The two mods seem to work OK together, but the Metamorphose fails to add all the correct parts when that mod is used. It half-way works, but leaves a Pawn basically without hands, feet, shins, forearms, etc.