Contradiction with Matthew 12:39
Jesus says a wicked generation seeks after a sign, while in Luke 11:29, Jesus speaks of giving the sign of Jonah to the generation.
Matthew 12:39: But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:
Contradiction with John 14:11
Jesus encourages belief based on the works he does, suggesting signs can lead to belief, which contrasts with the caution against seeking signs in Luke 11:29.
John 14:11: Believe me that I [am] in the Father, and the Father in me: or else believe me for the very works' sake.
Contradiction with 1 Corinthians 1:22
Jews require a sign, which contrasts with Jesus' statement in Luke 11:29 that no sign will be given except the sign of Jonah.
1 Corinthians 1:22: For the Jews require a sign, and the Greeks seek after wisdom:
Paradox #1
A possible contradiction in Luke 11:29 could be that while it criticizes people for asking for signs, other parts of the Bible show God providing signs to guide or reassure people. This might seem inconsistent because sometimes signs are given, and other times they are discouraged.