There are several duplicate passages in the Bible:
Is redundancy in the Bible a problem? When we consider the claim that the Bible is God-breathed and infallible, we tend to assume that means the Bibles we have today are perfect in every way and that a perfect book wouldn't be redundant. What we need to consider, though, is whether or not redundancy prevents the Bible from accomplishing God's purpose for it or from being accurate and trustworthy.
The objective of the Bible is to teach us certain things that God wants us to know. In order to accomplish that objective, it needs to be accurate and trustworthy. If things like minor copyist errors and translation errors don't prevent God from using the Bible to teach us, then redundant passages certainly don't prevent it either. As for accuracy, duplicate passages serve to keep the Bible's integrity intact (and in the case of Proverbs, to reinforce certain lessons). For instance, since the content of Chronicles overlaps a lot with Samuel and Kings, when copyist errors creep in, we're able to detect them and determine what the correct number or word is.
2 Kings 18:13 - 20:11 and Isaiah 36 - 38:8 relate the same events, and a large portion of the texts are the same (2 Kings 18:19 - 20:3 and Isaiah 36:4 - 38:3). 2 Kings 18-20 is an account of King Hezekiah's life, and the book of Isaiah relates Isaiah's life and prophecies. Since King Hezekiah and Isaiah were contemporaries and interacted, it makes sense that the accounts in Isaiah 36 - 38 should also appear in 2 Kings.