Moe's hat and the clock fall to the ground when he runs to the water trough after eating the pepperinos, but when Curly follows in his direction after eating them, they are nowhere to be seen.
When Curly is fishing for the mackerel, he puts one hand above the reel and another below the reel, but in the next shot, they are above it.
When Curly is fishing for the mackerel, the meat cleaver is embedded in the chopping block. When he throws the mackerel back, the meat cleaver is lying on the chopping block, up against the can of peanuts. When he reels in the rubber boot, the meat clever is several inches from the can of peanuts.
When Moe gets knocked down with the swinging doors, his apron is fully open in the back. He get knocked down a second time and it is still opened. But when he crawls under the door, the apron is wrapped around his entire back legs. It is also noticeable that he has tears in his eyes, suggesting that he was hurt for real.
When Curly and Moe chase after Thunderbolt during the race, it is clear that the bucket of water they have has no bottom to it, when the race is over.
Larry's yelling is obviously dubbed in when he gets his bottom stuck on the rake and when he is thrown onto Thunderbolt.
When the customer eats the pepperinos and is furiously drinking a pint of water, you can see a hose draining the water down to his elbow.