Plot hole: When the cop shows Pam the newspaper clippings they include what look to be fresh photos of the real Jason from the events of Part IV, yet no photographer is ever seen taking pictures of Jason alive in the previous films and most likely wouldn't live long enough to publish the photo. (01:25:00)
Plot hole: When the couple go into the woods to have sex, after they finish, the guy goes to a pond to clean up, which is not very far from where he left his girlfriend. A couple minutes later, "Jason" is about to kill her, and she screams very loudly. Despite this he doesn't hear her.
Plot hole: After Roy is knocked out of the barn doors, Pam and Reggie slowly walk over to look, but then Roy jumps up and grabs onto the barn floor. However when we see a wideshot of him dangling, you can see there are no ledges for him to have gripped onto while he fell, and that it's just a flat wall. Therefore he couldn't have popped up because there weren't any ledges for him to have grabbed a hold of on the wall. He should have instantly fallen on the tractor harrows. (01:18:45)
Plot hole: When Robin goes to bed you can see that Jake is not there. When she turns over Roy couldn't possibly have put Jake there in that short time without her noticing, not to mention that she was still awake. (01:03:30)