Other mistake: Where were the crime scene people? Jessica goes to her mom's house and her friend from the diner is cleaning up the blood? Highly unlikely.
Suggested correction: We don't know how much time has passed since she was killed. Crime scene people would have come and gone. And what's wrong with her friend cleaning up the blood? She's just being a good friend.
I highly doubt in a murder scene the police would make you clean it up! Think about that.
That's absolutely what happens: https://www.aftermath.com/content/who-cleans-up-murders/. https://www.biohazardresponse.com/blog/three-things-you-need-to-know-when-your-home-is-a-crime-scene/ Once evidence is dealt with, everything left isn't the responsibility of the police to clean up. Most people would hire cleaners rather than do such an unpleasant job themselves, but it's the responsibility of the property owners to clean.
That's just your opinion. Unless you know police procedure in every state then you can't make that assumption.
Revealing mistake: Jason is being bombarded with gunshots and the machete isn't damaged at all. The bullets magically bounce right off it. And "spark".
Plot hole: It appears no one even did the slightest bit of police work in the murder of Jessica's mother, if they had they would have seen evidence that Steve's story was true. Like evidence of someone going out the window and the cop's fingerprints on the knife.
Other mistake: When Jessica first goes to her mother's house after her murder, her friend asks why she didn't tell her about the baby. Jessica says she was going to tell everyone but didn't expect to be back so soon. She just told her mom on the phone she was going to visit the following weekend so yes she did.
Continuity mistake: When Steven fights the possessed sheriff at Diana's house, they hit the table knocking the lamp on the floor. You hear it shatter yet it's still lit.