Contradiction with 1 Kings 7:23
Explains the dimensions of the molten sea differently than the engineering accomplishment described in 2 Kings 20:20.
1 Kings 7:23: And he made a molten sea, ten cubits from the one brim to the other: [it was] round all about, and his height [was] five cubits: and a line of thirty cubits did compass it round about. [from...: Heb. from his brim to his brim]
Contradiction with 2 Chronicles 32:30
Credits Hezekiah with building a pool and a conduit, but does not mention the "other acts" that 2 Kings 20:20 refers to.
2 Chronicles 32:30: This same Hezekiah also stopped the upper watercourse of Gihon, and brought it straight down to the west side of the city of David. And Hezekiah prospered in all his works.