Episode #1.4 - S1-E4
Other mistake: A major plot point is the rivalry between the Wehrmacht and the SS, who refuse to work together. After the explosion at the cemetery, it is the Wehrmacht who are explicitly described as rounding up and interning suspected resistance fighters, with the SS not being party to it. However, when Archer visits the internment camp, most of the staff are wearing SS uniform.
Episode #1.1 - S1-E1
Other mistake: The German officer in the pub is described in the credits as an unteroffizier (corporal or, generically, NCO). He actually wears the uniform of an oberleutnant (lieutenant), a commissioned officer.
