The courtroom scene takes place in a California state court, but the wall behind the judge bears the Great Seal of the United States, which would only be found in a federal court.
Despite being featured properly as negligent, it's actually not a requirement to latch in a booster for the child to sit in it safely. It is recommended to latch a booster to prevent it from becoming a projectile in an accident when the child is not seated in it, but it is not needed when the child sits in it.
Charlie says he's "taken a residency at UCLA. I'm directing two plays at REDCAT." REDCAT is the performing arts center of CalArts, not UCLA.
Henry makes coffee for his mother and she takes a sip, but the cup is empty.
When Charlie takes Henry trick-or-treating on Sunset Blvd., they walk by a bus stop advertising the movie Love, Simon (2018). The majority of the movie takes place in the fall of 2018, whereas "Love, Simon" was a spring release and would have been on home video/streaming services long before the events in this film take place.
Singing by the women does not always synch.
While Henry and Charlie are talking after going trick-or-treating, Charlie's voice and laugh does not synch with the video while he's speaking about the play in Denmark, around the 1:10:00 mark.
Camera's shadow is visible on Nicole's back when she comes out from the subway station at the beginning of the movie.