Other mistake: When Sarah is at her Aunt Mitzi's house looking at the yearbook picture of Beau Burroughs, Beau's name appears on the top of the list, yet his picture is farthest to the right in a row of pictures. Yearbooks list names with the top name being on the left, and the last name on the right.
Continuity mistake: Jennifer Aniston and Kevin Costner are at the bar after she meets "B.B." after the conference in San Francisco. As he said "I can't be your father", Kevin Costner's left hand suddenly jumps to his chin as the shot changes from a side shot to one behind him.
Continuity mistake: In the bathroom scene where Jennifer Aniston is taking a shower and having a comical heart to heart with Shirley McClain, just after McClain says "And, don't call me grandma" she approaches the shower and screams Kevin Costner's name. There is a quick but very noticeable change in the shower curtain/towel position as it is lifted by McClain along with a vocal shift. Quick, but it's there.