For those keeping score at home, yet another strange problem with Portland's well-intentioned-but-troubled arts tax has come to light. This time, says Mayor Charlie Hales' office, it's that the city has been collecting its $35 from people living off state pension and/or Social Security checks—income sources the city is technically barred from considering for tax purposes.

And that means the city now must figure how out how to pay some of that money back. The snafu affects anyone who relies on entitlements and—crucially—didn't also earn more than $1,000 in eligible income from a part-time job or what have you. That $1,000 income threshold, approved in March, was the first big change for the arts tax. Hales is commissioning a broader review of changes, due this summer.

“This arts tax puts us in a bind,” Hales said in a statement. “We want to be true to voters, who approved it in November. We have to be good stewards of taxpayers’ money. And we want to support the public schools and arts community. These problems – which stem from the way the tax was written – make it difficult to meet all those goals.”

The city's revenue bureau isn't sure how many people qualify for the refund. Revenue Director Thomas Lannom, however, says $4.25 million has been collected so far. With eight days before the new May 15 deadline, that's about half of what officials said they expected to collect for the tax's first fiscal year.

The arts tax was approved by 61 percent of voters and is expected, pending legal challenges, to pay for school arts teachers and also help nonprofits and arts institutions expand access for low-income kids and other free programs.