Factual error: At the start of the scene where Jimmy films a commercial at the school, kids are shown on the playground. Many of them are wearing leggings or skinny jeans. The episode is set in 2002, when the trend was flare and straight legged jeans. The skinny jeans and leggings trend didn't become widespread until 2009 or 2010.
Continuity mistake: Mike is sitting in a diner as a waitress is walking up to him. The shot is from outside the window and shows the reflection of a mixed race couple walking across the street towards the window. When the shot changes to the waitress coming up and bringing him his drink, there is suddenly nobody in the street at all or around that could have been making that reflection. (00:31:20)
Answer: It might be the Panavision cap he wore when directing his terrible commercials.