An early tax break for medical marijuana patients may be short-lived, with state leaders rushing to reverse a recent ruling that could cost the state millions of dollars over the coming year.

“We are looking at a legislative fix but also have a request in to the Attorney General to give a more definitive ruling,” Fiona Ma, chairwoman of the Board of Equalization, said Friday.

The state board on Thursday sent notice that anyone who has both a doctor’s recommendation for marijuana and a county-issued ID card identifying them as a patient no longer has to pay state sales tax thanks to Proposition 64.

The measure, which passed Nov. 8 with 56 percent of the vote, made it legal for Californians to consume weed for pleasure.

The measure also states that all marijuana sales – both recreational and medical – will include an excise tax of 15 percent starting Jan. 1, 2018. But the initiative exempts medical marijuana patients who have county ID cards from regular state sales tax, which runs between 7.5 and 10 percent in California cities.

The problem is that Prop. 64 didn’t specify when the sales tax reduction for patients would kick in.

State Board of Equalization members – several of whom openly opposed Prop. 64 – ruled that the tax exemption for medical marijuana patients became effective Nov. 9.

The authors of Prop. 64 called that ruling “absurd,” since it directly contradicts the measure’s intended goal to generate more tax money for the state.

Ma said she agrees that it’s clear the tax holiday for medical patients wasn’t intended to start until the 15 percent excise tax kicks in so that there wouldn’t be a loss of revenue. She said her office is working with Prop. 64 advocates along with the governor’s office and other state leaders to change the policy.

A spokesman for Gov. Jerry Brown deferred to the Board of Equalization for comment.

If Attorney General Kamala Harris weighs in, Ma said the tax break could end quickly. If they have to wait for the State Assembly and State Senate to take up the issue, even with an emergency bill, they’d be waiting until the next legislative session starts in January.