During the parent/teacher conference, the word "ASSHOLE" onto the chalk board changes the writing style four times.
When Cal and Jacob are in the gym/sauna together, Cal's hair is long though he got a new hair do/cut a few scenes before. It is cut again in the scene afterward at the bar.
When Bernie finds out that his daughter is in love with Cal he drives over to the house where Emily and the Weaver family are living. When he runs around the corner of the house, Robbie immediately calls out "Jessica!" even though she is not yet visible and Robbie can therefore not know Jessica is also coming.
When Robbie is texting Jessica during school hours the time on Jessica's phone says 9:04 P.M.
When Jacob summoned Cal for the first time in the bar, Cal's drink does not have ice anymore but when he approached Jacob's table ice magically appeared in the drink. Also, the orange slice on Jacob's drink shifted to another position when he asked Cal to take a seat.
(at around 1h 40 mins) The man in front of Cal is "recording" with the lens cap on.
When Cal begins telling Emily how to re-light the water heater pilot he tells her to open the gray door by sliding it down. As he finishes the directions he tells her not to forget to slide the gray door, "back down", presumably to close it.