What went wrong for Hezekiah after he prayed and was given a sign?

The chapter says it in two verses. "But Hezekiah didn’t reciprocate appropriate to the benefit done for him, because his heart was lifted up. Therefore there was wrath on him, Judah, and Jerusalem" (32:25). "However, Hezekiah humbled himself for the pride of his heart, both he and the inhabitants of Jerusalem, so that the LORD’s wrath didn’t come on them in the days of Hezekiah" (32:26). In Hebrew his heart was lifted up is gavah with libbo, his heart, the same words as of Jehoshaphat (17:6) and Uzziah (26:16); chapter 17's honest question sets the three verses side by side. The chapter doesn't say what Hezekiah should have given back, beyond what these two verses say. 2 Kings tells of this time differently: the envoys from Babylon, Hezekiah showing them his treasures (2 Kings 20:12-15), and Isaiah's word, "Behold, the days come that all that is in your house, and that which your fathers have laid up in store to this day, will be carried to Babylon" (2 Kings 20:17). 2 Chronicles doesn't say whether "in the days of Hezekiah" (32:26) looks to that word, and these notes don't join them. 2 Kings 20's honest question sets out the two main ways Christians read Hezekiah's answer there (2 Kings 20:19); one view points to 32:26, the other to 32:25 and 32:31.