During the second malt shop scene, Patty and Richard are sitting across from one another at a table. During their conversation, a black male student approaches and sits at the table directly behind Richard. Another shot establishes this position, but when the angle changes, we see the same black male student entering the malt shop through the front door, while Richard's dialogue never skips a beat.
Near the end of the final scene where Patty and Cathy are playing Scrabble, Patty has two remaining tiles in her rack, which is positioned at the corner of the playing board. The doorbell rings and the angle of the shot changes. With this new shot, several tiles have returned to Patty's rack, which is now suddenly positioned along the side of the board.
When Patty goes to the library, none of the books have any library markings on spines that would enable anyone to shelve or locate them easily; in addition, all the books are old and frayed, suggesting they'd been published many decades before and making them of dubious value for a mid-Sixties reference collection.