When Maureen is slowly walking into the pool for the first time, she is already wet.
During Barry and Maureen's do-over kiss after the Tommy concert, which actor's nose is closer to the camera swaps from shot to shot.
When the cast returns to start season 2 of The Brady Bunch, they are working on Katchoo, where Jan is allergic to Tiger. This had already aired in season 1.
While filming the first season, The Brady Bunch boy actors are shown crashing the set of Star Trek (1966) and stealing props. The final episode of Star Trek was filmed in the early months of 1969, before the pilot of the Brady Bunch was even produced. During The Brady Bunch's first season, Star Trek had already been canceled and its sets destroyed.
The film incorrectly depicts the tag scene of "The Hair-Brained Scheme" as the last scene to be filmed of the series. In reality, the scene in Greg's attic was the last scene of the show ever filmed.
Maureen is wearing a 1980s style bikini during the pool scene, which is set in 1972.
When Barry, Chris and Mike take their 1969 joyride on a scooter through the Paramount studio lot, they pass by a Volvo F7 cab-over truck, which didn't exist in the United States until at least 1979.