King Asa

QUESTION: How could Asa have been perfect all his days in view of the bad conduct of which he was guilty in the latter part of his reign? See II. Chron. 15:17; 16:2, 10, 12.

ANSWER: No other answer can be given than that his apparent eclipse of faith was due to an eclipse of  intellect in the last years. In other words, that he was irresponsible because he was insane. That is my charitable explanation of the sudden change in his conduct. In that case God could pronounce his heart perfect while his head was awry. The commentators with great unanimity skip this verse.

— Steele's Answers pp. 244, 245.