When Jonathan first walks into the lake to look for the pendant, he walks in up to his waist. A minute later, when he walks away from the lake, the watermarks on his sweatpants only come up to his mid thigh.
(at around 57 mins) As the little girl rides away on her bicycle after talking to Jonathan, she rings her bicycle bell. However, as can be seen in the shots immediately beforehand, there is no bell on the bike.
When Jonathan's father is possessed by Pinker and Jonathan is arrested and placed in the squad car, his friend breaks the back passenger window to free him. When Jonathan's father gets in the car to chase him, the window is up and intact as he speeds away.