Albert Barnes Commentary 2 Kings 12:6

"But it was so, that in the three and twentieth year of king Jehoash the priests had not repaired the breaches of the house." — 2 Kings 12:6 (ASV)

For some time, no money had been brought in. Perhaps it was difficult for the priests and Levites to know exactly what proportion of the money paid to them was rightly designated for the temple service versus their own support, and consequently, what balance remained that they should apply to the repairs.