When Eleven/Jane reaches out to touch Kali's face, most angles show her right hand outstretched, but in the first shot of eleven touching Kali's face, it's her left hand.
When Kali and Jane (Eleven) meet and are talking on the pier, the Chicago skyline is the backdrop. A handful of the buildings did not exist in 1984; and were not built until the 1990's.
When El is with her sister in Chicago, the diamond pattern of the Crain Communications Building is visible in the background. In order for the building to be viewed at that angle and at that apparent distance, El and her sister would need to be standing in Lake Michigan. It is an impossible location.
Just after arriving in Chicago, Eleven looks the wrong way when crossing the street. This is because Millie Bobby Brown is British and they drive on the opposite side of the street.