Other mistake: When the Beatles are playing cards and singing "I Should Have Known Better," Paul (who shouldn't really be singing anyway) flubs the first line of the last verse. He sings "I sh... [laughs] never realized..." John does almost the exact same thing when they sing "I Should Have Known Better" in the concert scene.
Continuity mistake: There is a scene in the movie where the Beatles enter a limousine, I believe at the beginning of the movie. In this particular scene the Beatles are all dressed in suits and ties, but when the Beatles are filmed in the limo, John Lennon is wearing a turtle neck sweater beneath a blazer.
Grandfather: It's your nose, you know. Fans are funny that way, they take a dislike to things. They'll pick on a nose.
Ringo: Aw, you pick on your own.