Continuity mistake: Early on in this episode, Mr Burns says something like "this positivly has to be there overnight", the shot goes closer on every word or so. You can see that the background behind Mr Burns is that of the Plant. But when the shot zooms out, the background is now of one of the corridors.
Continuity mistake: When Ray Patterson's / Homer's office is shown, the text on the door is different according to the different shots. When the shot is on the door, the writing on the window (Name and Sanitation Commissioner) is close together, but when the shot is from inside the office with the door open, the writing is apart.
Continuity mistake: When Marge comes to pay for her shopping, she empties her left pocket on her coat, but when Sanjay finds it in her pocket, it's in her left pocket. We know it wasn't in her pocket anyway because when Sanjay finds it, it is bigger than the size of her pocket.
Continuity mistake: At one point in the episode, Homer is on the phone with someone in his work station. I forget who it was, but anyway, when you first see him, the wire is coming from the left side of him and when he turns to his right, the wire is coming from the right side of him.
Continuity mistake: In 'Time and Punishment,' the blue button on the toaster occasionally differs from being at the bottom of the lever to suddenly at the top, visible in the first shots of Homer fixing the toaster and between shots after Homer sits on the pink fish. (00:09:25 - 00:12:45)