Revealing mistake: In the first scene on Ginger's sister's boat that's being refitted, one of the seagulls (yes they used real seagulls) flies over the stern end right into the cyclorama and takes a nose dive to the stage floor.
Factual error: Charlie Chan claims that mixing hydrochloric acid with ferrocyanide of potassium is mixing two acids. Ferrocyanide of potassium is not an acid. (00:27:00)