Other mistake: When Cecil and Gloria are having their birthday celebration, before they are informed of Charlie's death, Cecil goes to the refrigerator to open a bottle of champagne. We hear the distinct pop of a cork from a bottle of sparkling wine, so we know he chose that bottle, but when he enters the living room a few seconds later, he is holding a glass of non-sparkling wine (no bubbles are visible).
The Butler (2013)
1 other mistake - chronological order
Directed by: Lee Daniels
Starring: John Cusack, Forest Whitaker, David Oyelowo, Michael Rainey Jr., Lenny Kravitz, David Banner, LaJessie Smith
Factual error: A scene near the beginning of the movie when Forest Whitaker and Oprah are both speaking on different phones. The phone that Forest is using has a modular plug. The scene takes place during the Kennedy administration (early 60's). The modular phone plug was not patented and put into use until 1975.
Cecil Gaines: I don't think God meant for people to not have a family.