When Ash and Telly enter the Long Island house it is daylight, but as they go through the house it is night (Ash is in the dining room with a lantern and there is complete blackness in the windows).
Before Telly starts tearing away the wallpaper in Ash's office we see a framed Hockey Jersey and five smaller framed pictures on the wall hanging over a desk. When she starts cutting the paper everything is still there, but the desk has been moved. Then when we pull back the only thing left is three small picture frames; everything else has disappeared.
When Ash smashes a large window to exit from the house on Long Island, after the glass has shattered and fallen, there is still glass along the top of the frame as Ash and Telly start to walk through the frame. However, when the shot cuts to outside, we see them stepping through the frame and there is no more glass along the top of the frame.
When Telly is running away from NSAgents for the first time, she runs into the store and we see a shop assistant standing behind the cash desk. In the next shoot, when the NSAgent runs into the store, there is not only the man but also a girl behind a cash desk - she wasn't there in the first shoot.
Julianne Moore's character is wearing a knee length black sweater when she runs away from nsa agents. Next shot of her walking on the bridge (and for the rest of the film) shows her wearing a shorter black sweater.
When Detective Pope arrives at the Long Island house, she has a blue light flashing in the front of her unmarked car. The NYPD does not use blue lights, they use red lights in their unmarked cars.
Julianne Moore's character is placed in the NSA agents' vehicle, which was shown to have New York license plates. Unless the agents were allowed the use of an NYPD or other state or local agency vehicle, the car should have white "US Government" license plates.
As Anne fires her third shot at the strange man walking away from her, there is a sound of a gunshot, but the view of her pistol shows no muzzle or breech flash, and the pistol does not cycle to eject the spent casing.
When the children leave for summer camp, there are no leaves on the trees.
The address for the house on Long Island that is given is only the street address and "Long Island." In actuality, Long Island is made up of many smaller towns and different counties. There should have been the name of a certain town included in the address, otherwise the house could have been located anywhere on the whole island.
Telly manages to encounter her husband again after disappearing with Ash yet he does not seem to remember her at all. This is an issue that is never addressed in the film again. In fact this character is never seen again after this sequence.
After the alien's attempt to make Telly forget her son fail, he is taken and everything is returned to normal in which the kids have returned to the world along with Ash Corell after he was taken. Anne Pope was taken as well yet her fate is left unknown.
When Telly confronts Eliot about Sam, Eliot acts like she has no idea what Telly is talking about whatsoever. This makes no sense. Even if her memory of Sam was erased by the aliens, as Telly's closest friend she would, like everyone else, have been given false memories of Telly's delusions after the miscarriage and react accordingly.