Double taxed state income generally occurs when you live in one state while working in another
state.
Usually the state where you live wants to tax your income no
matter where it was earned. Also, the
state where you earned the income wants to tax it because you earned it in that
state. Therefore, the income is taxed by
both states.
To overcome the double taxation, you can usually claim a
credit for taxes paid to another state on the resident state tax return.
In your case, if there
was a clear separation of income earned only while living in each state and you
are filing a part-year resident return for each state, then there should not be
any double-taxed income.
