Today, the Connecticut health exchange began the arduous work of calling thousands of consumers after a computer glitch resulted in wrong subsidy calculations for 5,784 Obamacare enrollees.

The malfunction is causing all sorts of headaches, as local news outlets are reporting. Insurers wrongly dropped at least 900 customers; around 3,900 Obamacare enrollees were wrongly considered eligible for government-funded Medicaid coverage; and an unknown number of people were overbilled for their coverage.

From the Hartford Courant:

[CEO Kevin] Counihan said Access Health CT discovered what he called a “system error” on July 1, though it knew earlier in the year there was a problem…

The system error has been fixed temporarily with a filter that was put in place July 7, Counihan said. A permanent fix will be installed July 18, he said.

The issue became public after two Republicans in Connecticut’s legislature wrote to Counihan on June 17 to ask about claims from constituents who said their insurance policies had been canceled. State House Republican Leader Lawrence F. Cafero Jr. and state Sen. Leonard A. Fasano, R-North Haven, also wrote a July 7 letter to the Insurance Department asking for information.

One woman in North Haven said her insurer, Anthem Blue Cross and Blue Shield in Connecticut, dropped her because it was given an incorrect tax credit by Access Health CT, Fasano said. She has since be reinstated, Fasano said.

That’s not all the bad news. Earlier this month, the CT Mirror reported:

Federal auditors reported Tuesday that they found deficiencies in the internal controls used by the health insurance exchanges run by Connecticut, California and the federal government.

The problems could have limited the marketplaces’ ability to prevent people from using inaccurate or fraudulent information when applying for coverage as part of the health law commonly known as Obamacare, the auditors said.

Connecticut’s exchange, Access Health CT, inaccurately determined that several hundred applicants were eligible for federal assistance in paying insurance premiums or health care costs, failed to promptly send enrollment information from 139 customers to insurers, and didn’t always verify the identity of people who use the exchange’s call center in accordance with federal guidance, the auditors reported.

And in June, the personal information of more than 400 Connecticut Obamacare enrollees was found in a backpack that belonged to an employee at a health-exchange call center. The incident is still under investigation.

— Jillian Kay Melchior is a Thomas L. Rhodes Fellow for the Franklin Center for Government and Public Integrity. She is also a Senior Fellow at the Independent Women’s Forum.