If you properly reported the Roth conversion by entering the Form 1099-R reporting the distribution from the traditional IRA but also included the conversion amount in the amount you entered as a regular Roth IRA contribution, as long as the total did not exceed the amount of the maximum regular Roth IRA contribution you could make and including this amount did not affect the amount that you might have been eligible to receive as a Retirement Savings Contributions credit, the extra amount entered as a regular Roth IRA contribution would not have affected your filed tax return and there would be no need to file the amended tax return. Only if the additional amount inappropriately entered resulted in reporting an excess contribution or an increase in the tax credit would you need to amend.
Even if the additional amount inappropriately entered did not affect your filed tax return, you'll still want to use your amended tax file when transferring into 2020 TurboTax next year so that TurboTax tracks your correct Roth IRA contribution basis.
