Cher Haavind, deputy executive director of the Colorado Department of Labor and Employment, says many overpayments stemmed from workers incorrectly reporting their earnings.

States can waive recovery of overpayments for most unemployment insurance when there is no fraud involved, but the Pandemic Unemployment Assistance program follows a different set of rules. It is administered as a form of disaster relief, and the statute that guides it blocks states from forgiving the debts.

Adding to the complexity, the PUA program gave new categories of workers—including gig workers and the self-employed—access to unemployment checks. But state unemployment systems were designed to calculate benefits based on traditional jobs, employer records, W-2 tax documents and verifying income with pay stubs. Re-engineering the systems to account for far more complicated self-employment income was bound to create problems, experts say.

In Ohio, thousands of workers have been overpaid through the regular unemployment-benefits system and Pandemic Unemployment