Continuity mistake: In a head-on shot, where Adolf Eichmann is the main character in the shot, he is shown lighting a cigarette, fully, and lowering his lighter. In the very next shot, he is shown from a side angle as a background character and again has the lighter to his cigarette, and lowers it, although it had already been lit in the previous shot.
Continuity mistake: Dr. Kritzinger can be seen standing looking out a window while the rest of the cast is sitting at the table, applauding something said by Kenneth Branagh. The camera angle then changes, the applause is still going on, and you can see David Threlfall suddenly sitting at the table. (00:26:25)
Factual error: All SS members have right collar tabs, except Heinrich Müller. His rank at that time was SS-Gruppenführer, same as Otto Hofmann, but his collar tab corresponds to SS-Brigadeführer (one step lower). For addition, the collar tabs of some general ranks changed after April 1942. The conference took place in January 1942, so they have older versions. But as I wrote, Müller and Hofmann were at the same rank, so the tabs should look the same.
Continuity mistake: When the car drives up to the house in the opening scene it has a D nationality plate -this is gone in the next shot.