At around 42 minutes when Ian walks outside to help Chris with the RV, the bloodstain on his shirt has disappeared. Moments later, when he is fleeing from a clown, it has re appeared.
At around 38 minutes, the gents try to start their vehicle and you can hear the starter motor cranking, but the engine would not start. They open the bonnet to find that the battery is missing.
If the battery is missing, no sound would come at all when you try to start a vehicle.
When Chris gets murdered by a clown while attempting to fix the RV, and the clown stabs him in the mouth with a windshield wiper, you can clearly see the tube under his upper lip where fake blood is being pumped out.