Summer is wearing a bikini top and bicycle shorts when she arrives for her surfing lesson with Slade. By the time she greets him on the beach, she is wearing a one-piece swimsuit, and she had no place to change.
When Summer is arguing with the Shooters, her hair keeps changing.
When the Shooters first spot the lifeguards, they turn around and run away. It then cuts to the one Shooter getting up in the surf, and then back to the whole gang, and they turn around and run away again.
Matt dives to tackle the blonde surfer and doesn't actually touch him, but the surfer falls down anyway.