When Victoria and Toddy are stealing a meal from the restaurant the wine glasses turn from one into two without the waiter bringing more and Victoria pours Toddy's glass without it being there but then it is.
The reaction shots of Andre and Toddy watching Victoria during her first "Shady Dame From Seville" number have them wearing the same boutonnières they wore during her very first show, but when Toddy and Victoria arrive back at the hotel Toddy has a different colored one.
At the restaurant when Victoria and Toddy first meet, she recommends that Toddy try the roast chicken. She calls the waiter over and start having a conversation about the wine. The waiter goes to leave saying to Toddy "I will think of a witty retort while I get your roast chicken", but neither Victoria or Toddy actually ordered it.
In both scenes of "Shady Dame from Seville", first with Victoria, the second with Toddy, the stars in the window behind the fountain keep changing positions. During close-ups, the arrangement of the lights (stars) differ from distant shots. Only once did the camera position change while following Victoria, where otherwise it stayed in one position, and should not have affected the position of the stars.
When Toddy and Victoria are in the bathtub warming their feet, Victoria is drinking out of a wine glass. When she finishes that bit of wine, she places the wine glass behind the ice bucket. However, there is a third wine glass in front of the ice bucket. When she goes to have more wine, she does not pick up the glass behind the ice bucket but the one in front that also has wine in it. There are three wine glasses for two people.
When King turns on the radio, the sound comes on right away. In the old vacuum tube radios of the day, the filaments of the tubes would have to warm up before any sound emanates.
When Norma is attacking King in the hotel suite and Squash steps in to protect him, Norma picks up a "decorative" spear and charges. Unfortunately, she charges a bit too fast, because she has to take a quick pause (half-step backward) to allow Squash to slam the bedroom door, which she then pierces with the spear.
In the second Chez Lui nightclub brawl, Madame President (the older woman who has her wig ripped off) is thrown up on the piano. When the piano collapses, it is seen to be made out of balsa wood or a very thin laminate.
The song Norma sings in the nightclub, "Chicago, Illinois," includes the line "maybe some day we'll have an airport." The movie is set in 1933. Midway Airport began operations in 1927 and by 1929 was considered "the world's busiest airport" with over 100,000 passengers annually.
After "Victoria" first reveals herself as Victor, Marchand checks his program and sees pics of both Victor and Victoria. The whole gimmick is the gender swap. Publishing those photos would blow the gimmick.