I just watched ESB for the first time since seeing Ep III. There is the scene where R2 fights Yoda for the lamp. Given that R2 was on the Tantive, and that R2's mind was NOT wiped (which, originally, to me, was a very cool idea) I couldn't help but wonder why R2 would do this. R2 should know who Yoda is, and should know better than to try to pick a fight with him.
I can't buy any notion of R2 just playing along, which I'm sure some apologists will try to suggest. In the end, it would have been better to have R2's mind wiped as well. Then this sequence in ESB wouldn't be at odds with the PT.