When Fletcher throws the chair at Neiman, the guitarist is behind Neiman in the first shot then missing in the second, probably removed to avoid being hit by the chair.
When Andrew and Fletcher meet for the first time while he is doing doubles Andrew looks up to see that Fletcher left and there is no jacket on the hook. When Fletcher walks back in and says, "Oops I forgot my jacket," the coat has reappeared on the hook.
When Andrew arrives late at the Dunellen Competition, you can see him putting on his jacket as he walks in the door. In the next shot, he's putting on his jacket again.
During the final scene, when Andrew is walking towards his father, he drops his jacket. He is never shown picking it back up and when he makes the decision to go back on stage he drops his jacket again.
Several times Andrew is bleeding badly and his hands are covered in band-aids. The next day he is fine.
In his retelling of the Charlie Parker/Jo Jones story, Fletcher says Parker went back to practicing the next day. According to Parker himself, he was so upset he didn't practice again for three months.
When Fletcher kicks the trombone player out of the band for being out of tune, he congratulates the alternate and tells him that he is now on the fourth trombone part. The player he kicked out was sitting on the end where the bass trombone would sit, but he was not playing a bass trombone. A top-notch college band would have a bass trombone player. And a jazz conductor would never refer to a bass trombone as a fourth trombone.
The band leader counts off by saying 5, 6, 7, 8, which is the way dancers count off. The way that jazz musicians count off is 1, 2, 1, 2, 3, 4.
In the studio band, we see close-ups of the saxophones' mouthpieces and ligatures. These are clearly not professional mouthpieces and ligatures; top college jazz players would be using only professional equipment.
In Andrew's first rehearsal with the studio band, we see the trumpet players placing their cases on the chairs and opening them. The cases are made of cheap plastic and are made for beginner-level instruments. Top college players would never be playing such instruments and would instead be playing professional instruments.
Some people believe 19-year-old Andrew Neimann would be unable to rent a car, suggesting that 21 is the minimum age. The minimum rental age in most states is 20, and in New York, where the film takes place, the minimum age is 18.
The auditoriums for the Overbrook and the Dunellen competitions are the same room.
Twice in the movie there are shots of trumpets where the film was reversed so it appears that a trumpet is the reverse of how it is actually constructed. As an example, on a real trumpet, the lead pipe runs along the right side of the trumpet, and in the movie, there are two shots where the lead pipe is running along the left side. It appears that this was done so that the direction of the band - director being shown to the left with the horns blowing toward the left from the right - could be maintained.
During the Caravan montage, there is a brief shot of the female trombone player playing with her left hand. Possibly a flipped shot.
When Andrew first goes into the Jazz bar to see Fletcher perform, the scar on his neck appears on the right side whereas for the rest of the movie the scar is on the left.
After oversleeping, Andrew slams his alarm clock as if to turn off his alarm. However, there is no alarm sound effect to be heard.
On line six of the dismissal letter from the Shaffer Conservatory, "2014" is mis-typed to be "2104".
The rental car that Andrew drives is a 2004-2007 Ford Taurus. Cars are only kept by rental firms for up to a couple of years due to the wear and tear they tend to go through, so this car is far too old for a rental car (this film is set in 2014). A dashboard shot also shows a mileage of over 100,000 miles.
A number of times during rehearsals, the soundtrack can be heard with trumpets using Harmon/Bubble mutes, but visually, the trumpets are shown with open bells (no mutes).
What Andrew is actually playing on the drums and what the audience hears rarely match up throughout the film. This is most noticeable in the final scene and is probably due to the fact that the drumming in so fast paced and intense that it would be nearly impossible to match.
When Andrew is at the dinner table to tell his family he is the new core drummer and is interrupted, you can hear an audio overlay of him saying "core drummer" again. The camera is on him and he is not speaking so it appears to be an editing mistake.
When Andrew sits on the floor and is listening to a drum solo by Buddy Rich, the CD case indicated that he is listening to "Buddy Rich: Birdland". The solo that he is listening to is actually from the end of "Channel One Suite" which in on the "Buddy Rich: Mercy Mercy" album which was recorded from Caesar's Palace in Las Vegas in 1968.
In the first competition, we hear the trumpet section playing during a long shot of the band that shows the trumpets resting.
The file is set in NYC, however, when Andrew breaks up with Nicole, you can see the windows of the café are partially obscured by diagonal metal poles -- clear indicators of earthquake retrofitting, done in California to older buildings that are at risk of collapse in a quake. Buildings in NYC would never have had this addition.
Fletcher calls out Andrew for rushing on the 7th take, and dragging on the 8th take. According to one contributor to Reddit who used Ableton software to analyse the seemingly imperceptible differences in tempo, Andrew was actually drumming faster on the 8th take.
In Andrew's dismissal letter from the Shaffer Conservatory, "in writing" is misspelled as "inwriting".
In the first rehearsal of the junior band, the conductor is seen conducting a very fast tune in four-four. A concert band conductor might do this, but a jazz band conductor would conduct it in cut time.
The alto saxophone players in the Shaffer studio band hold their instruments to their right side. Although this is standard for the tenor sax and other saxes that are larger than the alto sax, virtually all experienced also sax players hold the instrument directly in front of them (between their legs.)
When Fletcher drops in and asks the trumpets to play individually in the first rehearsal, the second player is supposed to make a mistake and does so, and sounds very bad. But anyone capable of playing in that band could never have sounded so bad; it was obviously an over-done mistake by someone who doesn't know anything about trumpet playing.