In a previous episode when Walter was watching the video where Olivia had set the room on fire they stated that she was three. In Subject 13 when the incident occurs she's clearly older.
The periodic table of the elements shown in the background as Walter enters his Jacksonville office clearly shows listings of elements up to element 117. Only the elements up to 109 had been discovered at the time frame of the scene.
The Real Ghostbusters (1986) wouldn't premiere until fall 1986, six months to a year after the time frame for this episode. There wouldn't be toys yet, and the ones shown came out several years into that series' run.
In the background of the 80s toyshop there is a shelf of Lego Atlantis, a range which wasn't launched until 2010
In the background of the 80s toy shop there is a shelf of Lego Atlantis, a range which wasn't launched until 2010.
In a scene where Peter is a boy with him mom in the 1980s she takes him to a toy store where all of the toys are from 2010 or later and some of them haven't been invented yet like magnatiles or all of the Melissa and Doug products.
Peter was taken from the alternate universe in 1985. In this episode, there are references within both universes that Peter's abduction happened 6 months prior, meaning it would have to be at least June 1985. However, in the videos that Walter records of Olivia, the date is seen as 4/1/85.