Give Me Something Good to Eat - S1-E2
Other mistake: Chucky's right middle finger is slightly but noticeably discoloured when he's talking to Jake in the bedroom near the beginning of the episode. It looks a bit more dull and grey than his other fingers. The "sculpt" also looks a bit rougher than the other fingers. It doesn't look like this in any other scene. (I'm assuming something happened to his finger during filming, and the special effects team had to rush to fix it during filming.)