SS benefits are not taxable in Ohio. You've done something wrong. The exclusion of SS benefits is so automatic, in TurboTax, that I'm having a hard time seeing how the mistake could be made. You may need to start over.
A possible explanation, you some how included SS on the retirement income allocation screens. Look a Ohio form IT NRC.
Ohio does a convoluted tax calculation for non-residents/part year residents. It calculates tax on total income, then it calculates a non resident/part year resident credit, which it subtracts from the tax it calculated on the total income. The credit is calculated as your non-Ohio income divided by Total adjusted Income multiplied by the total tax. TurboTax (TT) does this by allocating your income as either Ohio or non-Ohio. W-2 income will be allocated by the state name abbreviation shown in box 15 of your W-2. TT will ask you, item by item, in the state section, how much of your other income is Ohio or non-Ohio income. Make sure that your non-Ohio wages show GA (Other state postal abbreviation) in box 15 of your W-2 screen, with the GA amount in box 16.
This system allows Ohio to apply their highest tax rate, based on your total income, while only taxing your Ohio income.
Ohio has a nonresident credit allocation form.. IT NRC
http://www.tax.ohio.gov/portals/0/forms/ohio_individual/individual/2017/PIT_ITNRC.pdf
