Character mistake: Chad actually steps on first base before the baseman has the ball. He was safe.
Character mistake: The mob is marching to Homer, however they are going the wrong way. In the mob we see several people who all know where Homer lives. So why march the other way? (00:31:40)
Character mistake: After they get out of the hospital, in the background behind Kevin James, a poster misspells Cincinnati. It instead says "Cincinatti."
Character mistake: When Tracy's mom enters Motormouth Maybelle's place she is surprised to see her daughter. When she calls to her she says, "Tracy Edna Turnband" instead of "Turnblad."
Character mistake: When Randy is introduced for his semi-final match, he comes out to "Rock of Ages" by Def Leppard. The announcer says the song is by the "supergroup" Def Leppard. A supergroup is comprised of band members who were previously successful solo artists or band members prior to joining this band. Def Leppard is an original band. None of the band members were famous or successful prior to this band. (00:03:00)
Suggested correction: At best, this is trivia. Perhaps if the announcer was in the music business and knew the music jargon, it could be seen as a character mistake. I myself never knew "supergroup" had a specific meaning until you mentioned it. To me, it sounded like he just thought Def Leppard was super. Like calling them a totally radical group, despite no members being radicals - someone who wants complete political or social reform.
Character mistake: John would not be able to contact the John Simon Guggenheim Foundation to obtain his sister's application history. The confidentiality of applicants is strictly guarded and would not be shared.