I tried to change Atlarus (from metallurgy 4) to have the well-established trait, i used crafttweaker and both the material and the trait id are correct, but it doesn't seem to work.

atlarus:all:established

tried adding another trait to the atlarus, it worked.
also tried adding established to iron and didnt work.

EDIT:
it seems that removing the trait from copper removes the trait from other parts as well

This should be fixed in tweakers construct version 1.5.5