The Legend of Tennessee Moltisanti - S1-E8
Corrected entry: Chris is in a bakery and he is overlooked for a guy that walks in. The characters name is Gino, but later in the series the same actor shows back up as Vito Spatafore. They get into an altercation but if Vito was a wiseguy then Chris would have recognized him.
Correction: This is true, however it's really meant to be two characters rather than a mistake. He played the small part but was then later cast as Vito. They thought it would be OK because his original part was so small.