When Eddie/Palmer is finishing his breakdance moves at the mixer, his spin finishes with his left leg over his right and in the next scene, his right leg is over his left.
When Eddie is throwing rocks at his girlfriend's window, all of his dialogue is dubbed in as his lips don't move once, all while facing the camera.
The girl school mixer band's rendition of My Sharona in no way corresponds to the band's physical movements. There is not even anyone singing when the vocals are being heard.