The Protectorate of Bohemia and Moravia (German: "Protektorat Böhmen und Mähren" ; Czech: "Protektorát Čechy a Morava" ) was a protectorate of Nazi Germany established following the German occupation of Czechoslovakia. Earlier in 1938, with the Munich Agreement, Sudetenland territory of Czech Lands was incorporated into Nazi Germany as a Reichsgau.
The Sudetenland territory of Czech Lands was incorporated into Nazi Germany by the 1930's
The statement "The Sudetenland territory of Czech Lands was incorporated into Nazi Germany by the 1930's" is definitely incorrect because given the context it didn't happen until "1938, with the Munich Agreement". I think the system had difficulty with this because it didn't understand that 'by the 1930's' means before the beginning of the 1930's.  