Contradiction with Numbers 11:14
Moses expresses his inability to bear the people's burdens alone, contradicting him saying he judges the people alone in Exodus 18:15.
Numbers 11:14: I am not able to bear all this people alone, because [it is] too heavy for me.
Contradiction with Deuteronomy 1:9-12
Moses admits he cannot bear the people alone, whereas in Exodus 18:15, he states he judges the people alone.
Deuteronomy 1:9-12: And I spake unto you at that time, saying, I am not able to bear you myself alone:
Contradiction with Exodus 18:17-18
Jethro advises Moses he cannot handle the judging task alone, contrasting with Exodus 18:15 where Moses says he judges the people.
Exodus 18:17-18: And Moses' father in law said unto him, The thing that thou doest [is] not good.