When Alice records her speech on the PC, she says "I am you and, um, I have..." When she plays it later in the movie, the line is different.
Early in the movie Alice is seen running up the steep hill from Morningside Park, which lies just to the east of Columbia University. She then runs into the campus from the west. That is the moment when she first becomes disorientated.
(at around 29 mins) When Alice shows up late to teach her class, she quickly unpacks her laptop. When she's connecting the laptop to the projector, she suddenly has glasses on.
(at around 1h 17 mins) The toothpaste on Alice's hand changes shape.
In the credits, "In Dulce Jubileo" is credited to the "Worchester (sic) Cathedral Voluntary Choir. The word "Worchester" does not exist. The popular Christmas tune was sung by the Worcester Cathedral Voluntary Choir.
When Alice's daughter, Anna, shares with the family that she is pregnant, she says she is five weeks along and already knows she's expecting a boy and a girl. Babies don't develop reproductive organs until about the 7th week, but Anna had a genetic screen of the embryos done prior to implantation, which would have included sex information.