SACRAMENTO, Calif. (AP) – The California board that processes tax returns says it issued 23,500 refunds without verifying whether people had entered accurate wage information.

The Franchise Tax Board plans to start sending letters next week notifying anyone who’s received an improper refund because of the error.

Spokeswoman Denise Azimi says most of the people affected will see no change in their returns. The board is still evaluating those returns and Azimi could not provide a number of how many people received a smaller or larger return than they should have.

She says the error announced Tuesday happened over three days in March and was due to a technology glitch.

Azimi says the error doesn’t reveal other vulnerabilities in the state’s system.