When Valdar selects a volume from the small bookshelf in Frances' bedroom, the closeup tracking shot shows a different title on the book in the position of the book he is shown taking in the next shot. Also, the book he is shown selecting isn't seen anywhere on the shelf in the tracking shot.
The scenes in the German U-boats show great wide spaces and high ceilings unlike the cramped tight quarters on an submarine of that era.
When Valdar goes to turn on the lights in Sir Winston's library/office, the light coming in through the huge window is turned off a beat or two before the lights in the room come on.
When the Royal Navy car pulls away from Sir Winston's house after delivering the dispatches, a reflection of a large studio light is visible on the car's window behind the driver.