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)
Suggested correction: The picture was taken from security footage at the hospital after killing the 2 employees.
It was never shown.
Plot hole: When Freddy takes over Jesse's body at the party, there are several people watching through the patio doors when he confronts Lisa. None of these people ever make a sound, even when they see Lisa have a knife fight with a horribly disfigured man with long knives coming out of his fingers. The other party goers are completely oblivious to Freddy's presence until he comes jumping through the glass doors.
Plot hole: After Frank and Freddie accidentally release the trioxin gas, there are several shots of the gas entering a return air vent and traveling through the heating, ventilation and air conditioning system belonging to the warehouse. Finally the gas exits into the freezer directly on to a hanging cadaver. This room was previously confirmed as a freezer and would have had its own self contained refrigeration system with its own ventilation system. Typical freezer doors also seal as they close. The cadaver would have never come into contact with the trioxin gas and would have never reanimated.