When Sally (Jane Fonda) had Luke Martin (Jon Voight) over for dinner, she takes a pitcher of Margaritas out of the refrigerator which is about half full, without the foam. After she finishes mixing it on the blender, the pitcher is only shy an inch or two from the top.
Sally receives a letter from her husband, but she takes it from the mailbox at her new boyfriend Luke's apartment.
During the basketball game with the ventriloquist as the announcer, the microphone is at the puppet's mouth, not the human's.
Not only is Bob's long hair and mustache out of place for a Marine captain, there isn't a military haircut on any able-bodied soldier in the film.
The cans of Olympia and Miller Beer are the modern (1978) style of filming rather than the early 1970's models. The cans and bottles of Budweiser and Busch Bavarian are however the more appropriate early 70's models.
Most of the soldiers in the film have facial hair and long feathered, or Afro hair that isn't allowed among enlisted men.