If it's present on 2020 Schedule 1 line 19, your entries into TurboTax have told TurboTax that it's permitted to be a deductible contribution and that you want it to be a deductible contribution, not a nondeductible contribution. If you've chosen to treat it as deductible, the contribution doesn't get reported on on Form 8606.
If you want the contribution to be nondeductible and appear on Form 8606 instead of Schedule 1 line 19, revisit the Traditional and Roth IRA Contributions section and change the answer that you previously provided when asked if you want to keep the contribution as a deductible contribution.
