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.
Suspicion (1941)
1 other mistake
Directed by: Alfred Hitchcock
Starring: Cary Grant, Nigel Bruce, Cedric Hardwicke, Joan Fontaine
Continuity mistake: Johnnie, Lina and Beaky are playing anagrams. Lina spells out the word MURDER with an M as the first letter. The shot cuts away and then back again, and now the first letter is an inverted W. (01:01:40)
Isobel Sedbusk: I always think of my murderers as my heroes.
Trivia: Alfred Hitchcock's cameo occurs about 47 minutes into the movie. When Mrs Newsham parks her car outside the post office, Hitchcock can be seen putting a letter into the postbox.
Question: Was Lina supposed to open the necklace box when Johnnie gave it to her on the patio with the other gifts from the horse race? She tries a few times and can't.