Continuity mistake: Christopher is trying to start a fire with sticks and has a cigarette in his mouth. He starts to go back into the van with the cigarette in his mouth but in the next shot the cigarette is gone and he is rubbing his hands together.
Visible crew/equipment: When Jackie and his crew get to the poker game, an actor's red tape mark (double toe box type) is visible on the floor near the poker table. This will be where Carlo Renzi stands with his shotgun.
Continuity mistake: Towards the end of the episode Carmella is reading a book on real estate. When a close up of the book is shown, she is at the beginning of chapter 1, yet when the camera angle changes she is about halfway through the book.
Visible crew/equipment: When AJ tries on his new military school uniform, he's pressured to also put on the hat. Then, after AJ looks at himself in the mirror, just as he walks back toward his mother, the reflection of the boom mic becomes visible in that mirror directly over Carmela's reflection, at the right side of the screen.
Revealing mistake: Jackie is shot in the head, and not only does his head not burst, but the snow mount in front is already covered all over in blood before he falls.
Answer: That's not Jimmy, just a look-a-like. Jimmy's short and stout, the guy in "Christopher" episode is tall and medium built. The hair is also different.