Contradiction with Genesis 46:3-4
God tells Jacob not to fear going down to Egypt, as He will make him a great nation there, whereas Genesis 26:23 shows Isaac moving within Canaan, focusing on God's promise manifesting within the Promised Land, contrasting the location where God plans to develop His people.
Genesis 46:3-4: And he said, I [am] God, the God of thy father: fear not to go down into Egypt; for I will there make of thee a great nation: