Season 4 starts with Fiona (Emmy Rossum) telling Carl (Ethan Cutkosky) not to get used to sleeping on the top bunk since Ian (Cameron Monaghan) is coming back, but Ian always slept on the regular bed. Lip (Jeremy Allen White) slept on the top bunk until he got his own room in Season 3.
Although Fiona and Mike are supposed to be at a Bears game, the only thing that is correct are the colors. The logo on all the attire and jerseys are not official NFL.
It's incorrectly noted that Season 4 takes place one week after Season 3. However, it's stated that Fiona has been at the job for three months; this is the job she got at the end of Season 3 (benefits don't generally apply to temps). They state that it's just been one week since the last text received from Ian; in a later episode, it's stated that he has sent multiple texts.
Although on Showtime, Lip (Jeremy Allen White)'s college roommate is wearing a Game of Thrones (2011) (HBO) t-shirt.