When Nolan and Juarez are looking for a man in a mobile home, Nolan locates the man under a trap door, but the trap door is neatly covered by a small throw rug. It would be impossible for anyone to hide under the trap door and replace the rug neatly.
After the hit-man shoots Jason you hear him run the bolt on his rifle, two distinct sounds (bolt unlock and action cycle). This is only done manually on a bolt action rifle to load another round. The hit-man is using a AR-15 type rifle which auto-loads so there is no reason for him to run the action.
When Bailey is fighting Jason in the car, the car does not have head rests. This would allow the actors to move around in the car including pulling Bailey over the front seats. This wouldn't be able to happen with the head rests installed.
When Jason and Bailey are fighting in the car, she pulls his arm back and you hear a breaking noise. She wouldn't have broken his arm but she could've dislocated his shoulder which would make a popping noise.