Though Phoebe, the American Congresswoman played by Jean Arthur is not married, the actress's real wedding ring is visible in many scenes especially closeups during the latter part of the film.
When the Americans are flying over Berlin, the scenery outside Phoebe's (Jean Arthur) window never changes.
Nighttime scenes were filmed using a filter to darken scenes. BUT this technique leaves the sky light when in fact the night sky should be dark. Further, detail, both near and distance is vivid when in fact it should fade, disappear, into the shadows and darkness of the background.
Just after the movie begins, Phoebe Frost announces to the Army officers that she is the representative of Iowa's 9th Congressional District. The movie was shot, and set, after the end of WWII in 1945. Iowa's 9th District was eliminated by redistricting after the 1940 Census and ceased to exist after the representatives elected in 1942 - the first elections with the redrawn 8 districts - took office at the beginning of 1943. This error may have been intentional to avoid connecting her to a real postwar district.
When Pringle and Frost are stake-outing Schluetow's hobble, Schluetow comes out and the three of them have a conversation in post war Berlin. Now it being post war Berlin, it is not only bombed out, it also has NO streetlights. So, unless the moon is out, out in front of Schluetow's building is going to be pitch dark, meaning the scene where Schluetow analyses Frost's makeup is pure fantasy.