Contradiction with Deuteronomy 2:9
This verse contradicts Judges 11:22 by stating that the Israelites were commanded not to distress the Moabites or contend with them in battle for their land, yet Judges 11:22 mentions that they took land from the Amorites, which was Moab's territory beforehand.
Deuteronomy 2:9: And the LORD said unto me, Distress not the Moabites, neither contend with them in battle: for I will not give thee of their land [for] a possession; because I have given Ar unto the children of Lot [for] a possession. [Distress...: or, Use no hostility against Moab]
Contradiction with Numbers 21:24-25
It contradicts Judges 11:22 by indicating the Israelites took territory from the Arnon to the Jabbok from an Amorite king, seemingly ignoring divine command to avoid these lands, as implied in Judges 11:18.
Numbers 21:24-25: And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon [was] strong.
Contradiction with Deuteronomy 2:19
It contradicts Judges 11:22 by emphasizing that the Israelites were not to take possession of the land of the children of Ammon, whereas Judges 11:22 could be interpreted as suggesting they encroached on such territories.
Deuteronomy 2:19: And [when] thou comest nigh over against the children of Ammon, distress them not, nor meddle with them: for I will not give thee of the land of the children of Ammon [any] possession; because I have given it unto the children of Lot [for] a possession.