A close up the Playbill shows the number "Till the Clouds Roll By" is the 3rd song in Act One, yet when the number is over, the curtain comes down and everyone leaves the theatre.
When Charles Frohman sails to England, the pier worker removes a sign saying "S.S. Lusitania". The Lusitania was a Royal Mail Ship, thus it should have said, "R.M.S. Lusitania".
After leaving Club Elite in Memphis, Jerome walks to the Mississippi river docks where he is inspired to write the music for Show Boat. The river in the background is flowing in the wrong direction.
Kern did not miss the fatal sailing of the Lusitania because taking it was a last-minute decision: He was scheduled to sail, but missed the boat, having overslept after staying up late playing poker.
Kern did not meet his wife Eva Leale in a luxurious house where she had servants. He met her at a riverside inn owned by her father, where she was working behind the bar.
The electric sign and program for "Oh, Boy!" only mention Kern, the composer, not the authors of the book and lyrics, Guy Bolton and P.G. Wodehouse, who are not mentioned in the film, despite their many successful collaborations. (Bolton also wrote the original story for this film.)
After the Una Trance number, the cover shot of the audience applauding clearly shows one audience member in an aisle seat wearing an Army uniform of World War II vintage, even though the scene was set years before that. It indicates that was taken from stock footage.
When Jerome Kern is seated at the piano composing/speaking the lyrics to "They Didn't Believe Me", he is writing them on the sheet music. The camera then slowly zooms in on the sheet music and you can clearly see that all he added were scribbles.
During the "Girl From Utah" segment Dinah Shore is wearing a full skirt. She sits down and her skirt is bunched around her. There is a cut to the audience and then back to her. When it cuts back her skirt is now in a neat circle around her.
When Kern goes to see Sally at Club Elite in Memphis, he hasn't written Show Boat yet. Therefore, it would be before 1927. However, the song she performs with Van Johnson, "I Won't Dance", wasn't written by Kern until 1935.
No matter what year the story is taking place, Sydney Guilaroff's women's hairstyles, Helen Rose's costumes, which display her usual devotion to shoulder pads, as well as Lennie Hayton's musical arrangements, are all more or less in the style of 1946, which may have gone unnoticed by contemporary audiences at the time of the film's original release, but are strangely out of place and anachronistic today, particularly during the 1920s episodes.
When Jerome Kern arrives in Hollywood Esther Williams is signing autographs when he gets off the train. If this is Kern's 1935 arrival in Hollywood Esther Williams had not made her first film yet.
Eva Kern is supposed to be British, very British in fact, but Dorothy Patrick's very Western Canadian accent is directly opposed to achieving that desired effect.