Continuity mistake: Tony, Carmela, and AJ are meeting with AJ's school guidance counselor. Partway through the meeting, AJ is asked to leave. When AJ stands up, he is wearing beige-coloured trousers, but as the shot changes to show him walking out the door, he is now wearing black trousers. (00:15:30)
Continuity mistake: When Tony sits by the pool, the position of the towel on the chair changes through shots.
Continuity mistake: The table with the beer bottle by the pool gets closer to the chair after Tony sits down.
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.