Yea I wonder if that was ever addressed? I don’t remember the movies much and I never read the books but Vader must have seen, like, security footage or something and been like hey wait a fucking a second.
Oh yeah, I built that one. How did I completely forget about C-3PO? That's weird that I never mentioned C-3PO ever again since I was 9 even though building a sentient robot from scratch that can speak 6 million languages would make me one of the smartest living beings in the entire galaxy.