When Jem is eating the cherry pie at the diner, she initially sets down the fork so that the handle is facing towards her left side, at about the 7 o'clock position on the plate. In the next shot immediately following and without touching it, the fork handle is almost 180 degrees different, pointing at about the 2 o'clock position. It then jumps back to the original 7 o'clock position and repeats this pattern as the scene progresses. When the waitress brings the whipped cream, it is now sitting on the napkin to the right, completely off the plate, without having been touched, and then jumps to a brand new position on the plate.
When Jen and Judy get pulled over by the law enforcement officer at the very beginning, the position of the patrol car is directly behind Jen's vehicle through the rear window and he has the red and blue lights on. However, there are also red and blue lights shining on the left side of Jen's face that are far too large and in the wrong location to be a reflection from the driver's side rear-view mirror. When the scene changes to a shot from the passenger side looking towards the driver's side, there are now red and blue lights on the right side of Jen's face. The lights appear to be coming from the passenger-side side window. It couldn't be coming from the rear as Jen's seat and headrest would be blocking the light from that angle.
The Angeles Forest is 74 miles north of Laguna Beach. Antelope Valley is 64 miles further north of the Angeles Forest. The return trip from the Angeles Forest to Laguna Beach would not go through Antelope Valley.