BILLINGS, Mont. — U.S. Senate hopeful Troy Downing has been receiving California tax exemptions for claiming a house near San Diego as a primary residence at the same time the Republican said he was living in Montana full time.

Downing’s residency has been in the spotlight as he faces multiple hunting violations for the alleged illegal purchase of in-state hunting or fishing licenses in Montana from 2011 to 2016. Montana wildlife officials determined he was living primarily in California.

Downing has said he’s been a full-time resident of Montana since 2009 with a home in Big Sky.

But San Diego County property assessment chief Jeffrey Olson said Friday the Republican and his wife have received tax breaks worth about $76 annually since buying their house in Fallbrook, California in 2005 for almost $2 million.

Downing’s campaign said in response that the exemptions must have been a mistake — a claim Olson said was reasonable given that the exemptions are renewed automatically every year.

The Bozeman Daily Chronicle first reported on the exemptions.

“This is something that’s kind of buried in your tax bill,” Olson said. “It’s all pretty benign…The money’s not a big deal so we’re not knocking on doors asking if it’s their primary residence.”

Olson added that a notice has been sent to Downing asking if his primary residence is still in California.

Downing is among several Republicans seeking to unseat U.S. Sen. Jon Tester, a two-term Democrat who’s considered vulnerable after President Donald Trump’s wide margin of victory in Montana last year.

Downing campaign manager Kevin Gardner said the candidate would pay back any improper tax exemptions in California. He accused the “liberal media” and allies of Tester of “grasping at straws” and looking for ways to undermine Downing’s campaign.

“It is California policy to automatically renew a homeowner’s exemption and if it was done so, it was done without Troy’s knowledge,” Gardner said.