Other mistake: Steve Trevor is amazed at the existence of escalators and the DC Metro, despite subways and escalators being commonplace by 1917 (the time he's originally from).
Other mistake: Steve Trevor can't figure out an exercise bike or an escalator but has no trouble jumping in a modern jet and knowing how to start and fly it?
Other mistake: It's amazing the guy whose body Steve is inhabiting gets into the party. Clearly it's VIP and formal dress while he's dressed in casual clothes.
Other mistake: In the first Wonder Woman movie, Queen Hippolyta, Wonder Woman's mother, was adamant that Diana was never to be trained as a warrior, fearing the fact that making her stronger would draw Ares to her (or vice versa), and argues with her sister who was training her in secret when she finds out; this incident happens when Diana is an adolescent. In this movie, a much younger, still child-like Diana takes part (and nearly wins) a contest between the fiercest athletes, involving horseback archery. The Queen should be freaking out and look for whoever put a weapon in her kid's hand, and instead she is perfectly happy, obviously cheering for her and at the end she even gives her a pep talk telling her to look up to...the great warrior Asteria.
Suggested correction: Hardly commonplace - a couple of cities had small subways in the USA in the very early 20th century, and some early escalators, but neither would have resembled what Steve was seeing in 1984. Not to mention that given their limited use there's no guarantee he would have even had the chance to see or use any in his own time.
Jon Sandys ★
He also spent time in London during the First World War, where escalators were in common use for both Underground stations and department stores like Selfridges, which he visited.