Fight fans are seen milling outside the arena at night before the big fight. But when Larry Fine runs outside after breaking his violin, it is clearly broad daylight.
After Larry Fine steals the radio, he is shown running across the street almost getting hit by a car. A few minutes later he is shown crossing the same street almost getting hit again by the same car.
When Curly Howard gets back from lunch in the beginning, he has nothing in his hands as he has just come from outside yet in the very next shot, he has a small pad and pencil in his hands.
After KO Stradivarius beats up his opponent, the next scene shows the opponent's managers knocked out on the floor as well, yet we don't know how they got there.
In the shot of Mr. McGurn on the ceiling fan, the restaurant door is open; The Three Stooges then open the closed door as they leave.
The second time the timekeeper's bell is struck, it does not make the "clang" sound. It sounds properly every other time.
The cathedral-style radio that Larry Fine takes to the ring is a General Electric model K-64. He takes it from an RCA shop, but at the time GE made radios for RCA. It is plausible that the radio would continue to play after leaving the front of the shop, as they could be made to run on batteries. When the radio is seen at ringside, its front panel has been changed, doubtless part of the modifications made so it would do minimal damage to Larry when it was smashed down over his head.
It's obvious that the audience in KO Stradivarius' fight is stock footage from the 1920s, judging by the film speed, fashions, and orthochromatic film stock used, being shown in a continuous loop. Take a look at the guy in the middle of the footage who keeps shaking his friend's neck.
As Larry Fine runs down the street for the first time, a voice can be heard saying "Hold it!....Stand back!" (obviously the director or a production assistant asking onlookers to get out of the way).
The restaurant clock is stuck at 12 o'clock throughout all the initial restaurant scenes.
It is never explained how Larry knew to start playing "Pop Goes The Weasel" on his violin as Curly is being beaten up by the restaurant patrons. There is no indication that the characters actually knew each other beforehand.