Ernst Rohm is shown as early as 1931 wearing his special "Stabschef" insignia (a wreathed General's star) when in fact this insignia did not exist until after the Nazis took over in 1933.
As early as 1923, the Nazi storm troopers of the SA are shown wearing the classic brown Nazi uniforms, complete with collar insignia and shoulder cords. The brown uniform did not appear in the storm troopers until 1925, with standardized rank insignia becoming widespread in approximately 1929.
Ernst Röhm had actually left the Nazi Party movement after the failed Munich Putsch, and had become a military advisor in Bolivia until he was asked to come back to Germany by Adolf Hitler in 1930. The series completely omits this and implies that Röhm was in Germany the entire time helping Hitler rebuild the Nazi Party after 1925.