Other mistake: Early in the film, Jim Carrey is watching TV during a sports segment. He is watching Channel 7, the station he works for. This clip they showed was of actual WKBW sports director John Murphy. The clip they showed was taken directly from a real WKBW newscast, with the authentic news set, and graphics. However, when they show a clip of Ch. 7 News later, there are completely different graphics, and a completely different news set, both made for the movie.
Other mistake: When Grace is running after her fight with Bruce, she sees trees on her right hand side with "Bruce + Grace" and then "forever and ever" inscribed on the following trees. However, when Grace looks to see how far back this is written on the trees, she leans to the left side of the screen (or her right). This wouldn't allow her to see farther down the street, since it was written on the trees to the right.