State governments are not necessarily believing the same set of facts that the federal government does. I got caught in a multi-year cycle one time where the state government kept coming after me every year for the same thing, even though I had the federal return and the evidence that it was correct.

Each year I'd send that thing in, in response, and I'd never hear from them...until the next year, when they'd do it again.

Felt to me like each year somebody would receive my response, decide it was too much work to deal with, and then file it away in the "hit them again next year" pile.