When Michael is in the studio laying down the audio tracks for the song "Human Nature", the caption reads that the year is 1983. Human Nature was on the "Thriller" album, which had already been released in 1982.
When Jermaine and Hazel call Joeseph to tell him they're getting married, they're using a pay phone with push buttons. Jermaine married Hazel in 1973, push buttons on pay phones weren't widely used until the 1980's.
When The Jackson 5 perform the song "Never Can Say Goodbye", the actor playing Michael pulls an obvious mistake in mouthing the song. In the chorus, he adds the word "baby" in a spot where it doesn't belong.
At the pool party at Diana Ross' house, Marlon and Michael are talking to each other in the pool but their mouths don't move. When Joseph calls them out of the pool, Michael's mouth doesn't move when he says "5 more minutes".
During the montage of the group's touring experiences, there is a shot of the adult Jermaine character riding on the plane. After this montage, the movie continues using the teenage Jermaine character.
When Katherine catches Joseph on the phone with his mistress, while listening in on the outside phone, he hears her hang up and she is suddenly there, in the house. There's no way she could have been back inside the house so quickly.
When the boys are congratulating Tito on his engagement in the den Jermaine fixes some root beer floats. His float has not yet settled, but when he clicks his glass to Tito's it has settled. Then when he brings his glass back it is once again not settled.
When Jermaine arrives at the Jackson house to sign the CBS contract, he is shown driving up in his convertible, his hair is in a shorter, tighter afro. When he is shown inside the house, his afro is much longer.
In the scene when the actor who plays Michael Jackson is doing his solo performance for Motown, the single, glittery glove he is wearing is on his right hand. In the actual performance, the real Michael Jackson is wearing the glove on his left hand.
Before the brothers go on there first tour with Motown in 1970 they are shown in the recording studio listening to playback of "Rockin' Robin" Which wasn't recorded until 1972 on Michael's first solo album.
In the original Motown 25 performance of 'Billie Jean', Michael Jackson wore the sparkling glove on his left hand. In the portrayal of this performance in the movie, Michael is wearing the glove on his right hand.
When Joe invites Katherine into his room for the first time, he plays guitar for her. He is first shown from the back playing it left-handed, but the shot then immediately changes to show him playing from the front and you can see he's playing it right-handed.
During their performance at the Apollo, the strap on Jermaine Jackson's bass snaps off, nearly dropping the bass guitar. But since Michael Jackson's character is obviously the focus, this scene was never corrected.