When Sam and Luka are at the gas station, Luka is using the pump - supposedly for pumping gas. However, when Sam gets in the car, they show a side view of the pump and the lever, which controls gas flow into the car, is down, which means it's not pumping. A few seconds later, we hear a click which means the gas is done pumping.
Sam's hair changes from straight to curly and back to straight between shots.
When Sam finds Alex at the hospital, she puts both of her hands on his face, but in the next shot, it's just her left hand.
On Sam and Luka's drive to Iowa then Colorado, they're shown driving on various 2-lane highways. But the first 95% of that trip would be on Interstate highways, which are 4-lanes at a minimum.
The medical building said to be in Davenport, IA, has an address of 19110 Darvin. That address is for a medical building in Moneka, IL.
Sam tells the police that Alex is 12, but the season prior he was 10. It can't be that he was aged up because of the new actor, because Dominic Janes is nearly a year younger than the old actor, Oliver Davis.