When Riley and Jesse confront each other, Riley breaks a glass mug. The mug is first smashed to its handle, then next shot it is half a mug, then the next shot the half a mug is now missing pieces.
It was claimed that Cameron accidentally killed a gray feral pigeon in the beginning but when John sees the body at the end, not only is it brown, it is an entirely different kind of bird. However, they were two different birds and the obvious difference in appearance was intended to make the point that Cameron killed a second bird. This makes the viewer wonder whether she really killed the first one by accident, as she claimed.
Cameron states that rock doves are migratory. They are not.