Contradiction with James 1:6-7
Explains that one should not doubt when asking something from the Lord, whereas Exodus 8:12 shows Moses implicitly acting without such doubt as his prayer for relief is answered, implying a consistent faith.
James 1:6-7: But let him ask in faith, nothing wavering. For he that wavereth is like a wave of the sea driven with the wind and tossed.
Contradiction with Exodus 8:15
Describes Pharaoh hardening his heart after relief is given, contradicting the immediate deliverance and relief seen when Moses prayed in Exodus 8:12.
Exodus 8:15: But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the LORD had said.