Mass IRA Taxable

I am very confused about the MA taxable IRA requirements. My husband made two ira traditional contributions in plan years 2022 and 2021 for $7K each.  They were non deductible in MA.  In 2023, he converted them to a Roth.  $14,618.  

Since we received no deduction from the state, I would assume we would pay tax on the gain of $618.  However, in 2019, we inherited a small ira from his Mom, $15,400 of which we paid taxes on.

My accountant has used this distribution received in previous years to populate Line 3, hence we are now paying tax on $14,618 (Line 7) which is our gain and contributions.  This doesn't seem right to me.  Why am I being double taxed?