... the mistake began as soon as we started calling it a "blue-minimizing robot".

Agreed. But what kind of mistake was that?

Is "This robot is a blue-minimizer" a false statement? I think not. I would classify it as more like the unfortunate selection of the wrong Kuhnian paradigm for explaining the robot's behavior. A pragmatic mistake. A mistake which does not bode well for discovering the truth, but not a mistake which involves starting from objectively false beliefs.