You are correct that you should not be reporting the 2017 state and local refunds on your 2018 tax return if you did not receive the refunds in 2018. You report state and local refunds in the year that you actually receive the refund (whether or not you get a 1099-G).
Go back to the State and Local Tax Refunds topic in TurboTax for your 2018 tax return. On the State and Local Tax Refund Summary screen click the Delete button to delete the refund.
