When Harry Doolin and the other boys are bullying Bobby and Carol, Carol's hair clip changes its height from low forehead (at around 6 mins) to mid-cheek (at around 29 mins) (after struggling against one of the boys), up to eyebrow (at around 33 mins), down to low cheek (at around 44 mins) (again struggling), back to eyebrow (at around 3 mins), and down to low cheek (with no struggling).
The money that Bobby throws at his mother changes from behind her feet to in front of her feet.
The adult Robert opens the Fedex package containing Sully's baseball glove, and tries it on his right hand. Later in the film, the mitt is shown as a conventional left-hander.
When Ted offers Bobby the job of reading the newspaper to him as they are seated at the table in Ted's apartment, things move about on the table top. At 17:25, in a medium shot of Bobby from behind Ted, the cup, sugar and creamer, and Bobby's root beer are aligned. At 17:26, in a medium shot of Ted drinking his root beer from behind Bobby, the sugar and creamer have moved to Bobby's left out of alignment. At 17:29, in a medium shot of Bobby from behind Ted, the sugar and creamer have moved back, but Bobby's root beer has moved to his left out of alignment.
At the beginning of the movie, adult Bobby receives the baseball glove left to him by John "Sully" Sullivan. The premise was that it was left to him in Sully's will. That would've been impossible since Sully died in a car accident and Bobby went to his funeral. There would've been no time for the Will to have been read and the glove sent before the funeral.
Set in 1960, but when Bobby is reading the newspaper, he reads about Nixon running for Vice President, which he did in 1952 and 1956. Actually, the reference is to Vice President Nixon securing the Republican nomination for President, which he did in 1960.
The shot is flipped at the end of the movie when Bobby is riding his Schwinn bike. The kickstand is on the right side and the chain on the left (at around 1h 35 mins), opposite of where they should be (at 15:32-15:56). Also, note that one can clearly see the name "Schwinn" reversed on the side of the bike in this scene (at around 1h 35 mins).
Towards the end of the movie young Bobby is running to meet his mother as they move away. As she sits in the Rambler waiting for him she listens to a car radio that is not there-only chrome covers where dials should be, and a blank radio front.
In the beginning, when adult Bobby opens the newspaper clipping about John Sullivan's death, most of the text in column one is repeated in column two.
(at around 31 mins) A school bus with a retractable stop sign attached to its side stops and then continues on. School buses did not start using that design until the 1980s.
When Bobby picks up the payphone, we hear a modern dial tone (at around 1h 21 mins). That tone was not introduced until the late-1960s, along with the introduction of touch-tone dialing.
Set in 1960, but when Bobby is reading the sports pages, he reads that Maury Wills is breaking Ty Cobb's stolen base record, which happened in 1962.
When Brautigan relates the story of Bronko Nagurski's return to football in 1943, he states that the Chicago Bears played the "crosstown Cardinals" (at around 52 mins). Everything about this story is factual except the opposing team was actually the Washington Redskins.