Contradiction with Exodus 14:11
This verse expresses fear and doubt among the Israelites about their deliverance, whereas Exodus 18:8 describes the recounting of God's successful deliverance.
Exodus 14:11: And they said unto Moses, Because [there were] no graves in Egypt, hast thou taken us away to die in the wilderness? wherefore hast thou dealt thus with us, to carry us forth out of Egypt?
Contradiction with Numbers 11:1
The Israelites complain about their hardships, contrasting the gratitude and celebration in Exodus 18:8.
Numbers 11:1: And [when] the people complained, it displeased the LORD: and the LORD heard [it]; and his anger was kindled; and the fire of the LORD burnt among them, and consumed [them that were] in the uttermost parts of the camp. [complained: or, were as it were complainers] [it displeased: Heb. it was evil in the ears of]