The IRS cannot be sure that Americans who lacked health insurance last year have complied with Obamacare’s “individual mandate” penalty this tax season, according to an inspector general report Friday that pointed to a decision to delay proof-of-coverage forms from insurers and employers until 2016.

Agency managers told the Treasury’s Inspector General for Tax Administration that a “business decision was made to not develop processes and procedures” to ensure compliance after it decided in 2013 to delay the pair of forms. The documents are sent to both filers and the IRS, allowing the federal government to cross-check what filers say on their returns.

“The transition relief was intended to give the insurer time to adapt its health coverage and reporting systems to comply with the [Affordable Care Act],” the IG report said. The same was true for employers.

Obamacare’s health exchanges did report 2014 insurance details for its customers on a form known as the 1095-A, although more than 800,000 customers on the federal HealthCare.gov portal received ones with errors.