In one scene Amy makes several video calls trying to find out Megan's whereabouts. Her phone keeps recording her between two calls which is impossible since the video would stop the moment a call is ended.
After Megan arranges the date with Josh, she gets on a video chat with Amy. Just before Amy's video feed pops up, Michael Goi can be heard calling, "Action!"
When Amy gets slapped, the hand doesn't connect.
When Megan is telling Amy the camp counselor story, you can briefly see Megan's mom hand before she grabs the sheets.
After Amy has been slapped, the shadow of a boom mic can be seen at the door right to the stairs.