Why would a state send me an income tax bill after I moved away?

Start by identifying what the old state is asserting. It may be treating the client as a resident, a part-year resident, or a nonresident with state-source income. Those are different theories and they require different evidence.

A move does not automatically close a state-tax file. The old state may still have a prior address, old driver's license record, earlier resident returns, school records, withholding data, or missing-return information. The EA should build a year-by-year timeline showing where the client lived, where services were performed, what returns were filed, and what tax was paid elsewhere.

Do not answer only with "the wages were earned elsewhere." If the old state says the taxpayer remained a resident, the response may require a resident return with a credit calculation or proof that domicile changed before the notice year. If the old state says the taxpayer had source income, the response should trace the income to the correct state.

For EA exam purposes, the strongest answer is procedural and substantive: preserve the notice deadline, request account detail if needed, and respond with the right residency and income-sourcing evidence.