Near the end of the film, while Jeff is explaining how the media so quickly moved on from his story to the next new item in the news cycle, the new van parked in front of his home is a newer model Ford E-Series van than what was used at the time. While that body style of E-Series was in production at the time, lights and wheels of the van signify it as being from at least 2001 or later. Also, the equipment mounted on the van is not what would be common for that time.
When Tonya is competing in the 1994 Olympics, during the broken lace incident, we see that actress Margot is wearing almost new, pristine skates. Skaters wear the same skates used in their intense practices, where the skates get banged up and scuffed. If they switched to new skates for the competition, they wouldn't be properly broken in. Historic photos showing Tonya's skates during the lace examination, show the wear, partially explaining the broken laces.
When Tonya Harding competed, song lyrics were not allowed in competition the way they are today. Although she included "Sleeping Bag" by ZZ Top in the 3d section of her 1991-1992 program, it was the music only.
During the scene where Diane Rawlinson approaches Tonya to convince her to try out for the Olympics again at the back of the diner where Tonya works, you can see the electric meter behind Tonya is a "smart meter". These digital meters did not exist at this time of the movie.
In a scene depicting the rear of Cobo Arena in Detroit, tall pine trees and parking lot are shown. Cobo Center backs up almost directly to the Detroit River. A shot filmed there would show the river and the skyline of Windsor, Canada.