2 Kings 23:26

Notwithstanding, the Lord turned not from the fierceness of
his great wrath, wherewith his anger was kindled against Judah
Notwithstanding the great reformation wrought among them; for though Josiah was a sincere reformer, and did what he did heartily, as to the Lord, according to his will, and for his glory; yet the people were not sincere in their compliance, they turned to the Lord not with their whole heart, but feignedly, ( Jeremiah 3:10 )

because of all the provocations that Manasseh had provoked him withal;
by shedding innocent blood and committing idolatry, which the people consented to and approved of, and even now privately committed idolatry, as the prophecies of Jeremiah and Zephaniah show; and it may easily be concluded that their hearts were after their idols, by their openly returning to them in the days of the sons of Josiah.