When Seth racks up the balls at the pool table their positions change between shots.
When Frank and Clair meet at her Mom's house there is heavy rain in the background when the camera focuses on Frank and bright sunshine when camera is on Claire.
At the end of Chapter 40 while the Underwoods are in Texas, Frank says that the State Of The Union is in 2 week. The grass and trees are rather green for being Texas in January. Texas is actually pretty brown in January.