When Doris sends John a friend request, the date on her laptop reads 2014. In the following scene, when John and his friends are discussing Doris, one of them brings up the federal legalization of gay marriage, which was not legalized until 2015.
When Doris is at the diner with her co workers, the shots go back and forth with angles. Each time the angles change, the drink for the female co worker has inconsistent placement. In one shot she can be seen lifting it up to her mouth to drink, and the very next shot it is down on the table again and we can see her lifting it up to her mouth again. This continues throughout the entire scene.
When John messages Doris and asks where they have met, Doris says, "Yes. We met at a party in Malibu once." When the message appears to John the typing says YES but she had never typed yes only said it aloud.