[hef19898]

One good example are Battletech's Unseen Mech models. The stats were ok, the drawings were owned by some folks in Japan. Liscense agreements were impossible, so instead of risking a law suit, Battletech switched Mechs. And that required an in-universe retcon of sorts to explain why the Mechs everybody used and inhereted from their great-great-grandparents weren't there anymore.