Other mistake: In the opening scene of this German movie from 1944, a panoramic view of the city of Potsdam is shown with the subtitle "Potsdam 1813". In the background, the two high radio masts of the Potsdam Military Communication Central can be seen very clearly before the sky.
Other mistake: In the flashback of the denouement, Dr. Armstrong is shown dead face down on the beach, with the feet pointed ashore and the head to the sea. Mr. Owen takes also a sip from that Armstrong's flask and tosses it in the sand without capping it. However, Vera and Lombard found a corpse face inland and feet to the sea, and a flask with its lid in place. (01:28:50 - 01:34:40)
Other mistake: Daffy walks past the same table and couch four times. When he runs the other direction, he passes the same staircase five times.
Other mistake: When Charles tries to see if he can touch Elvira, he puts his hand behind hers, but we can't see the bits of his hand that are behind hers. Since she is a ghost we should be able to.