When "Fritz" (played by Lloyd Bridges) is speaking to his employer, he takes out a cigarette case, offers one to him, then removes one for himself. He taps it on the case. In the next instant, when the camera changes to the angle behind him, the cigarette is already in his mouth.
Lanyard is first seen in a hotel room getting dressed. He is sitting down with his tie undone around his neck. Without breaking conversation he is next standing and putting on his jacket and the bow tie is has been tied.
Despite Egypt being a British Protectorate, all the cars in Alexandria are left-hand drive.
When Mr. Cezanne is locking the door, a smudge on the back of his coat (upper right) shows a round smudge. A little later, he is shot dead and his back is shown. The smudge is now a darker (entry wound) spot is the same place.
When Donald Jameson (Robert Stanford) showed up with his 'fiance' (Ann Savage), he introduced her to Lanyard and Booth as Valerie, but immediately after, Booth called her Miss King - how did he know that?
Donald Jameson's accent is conspicuously American, rather than British as it's meant to be.
The final chase with the plane and the car is obviously not near Alexandria nor even in Egypt.
A cable can be seen pulling the limo into the elevator.
The Morse code on the lace thread is not in code nor even in German.