Other mistake: Detectives Dundy and Polhaus visit Bogart at 3:40 in the middle of the night as we see the time on his alarm clock after they walk in. In the previous shot it's impossible to tell what time it is time because there are no hands on the clock. (00:11:10)
Other mistake: When the invitation to the Hunt Ball is shown on the screen, it says that the ball is on Thursday, March 7, but on the night of the ball when Lena gets the telegram from Johnnie, the date of the telegram is March 8, 1938, which would have been the next day. And March 8, 1938, was actually a Tuesday and March 7, 1938 (the day of the Thursday Ball), was actually a Monday.