During the VJ dance sequence when Jimmy is initially trying to pick up Francine, the cherry in her drink disappears when she eats it in one shot. It reappears in her drink, only to disappear in subsequent shots.
In the opening night club sequence Franchise's jacket alternates between being buttoned and buttoned when she's seated at the table.
Set in the 1940s, many characters have 1970s hairstyles, facial hair, and clothing.
Out in the country, a parking garage with at least one 1970s-model car is visible in the distance.
A guitar appearing to be a Gibson ES-175 would not have been available in the 1940s. Even if it was, the humbucking pickups on it weren't around until 1957.
In some scenes, the soundtrack plays an electric bass when an upright bass player is on stage.