Alright, let's review this: "Amount shows as taxable."

A backdoor Roth is just a Nondeductible contribution with a nearly immediate Conversion. That's why it would be nontaxable.

Your taxpayer client would have made a Nondeductible Traditional IRA account contribution. So, confirm you entered this part correctly.

The function of "backdoor" requires there to be no funds in similar deferred accounts, so that there is no amount pre-tax or untaxed. That's because converted Basis is nontaxable. If there are any earnings or previously deducted (pre-tax) funds in any of the account types (per the instructions on the Form 8606), then the conversion, as usual, is Pro Rated for taxability.

So, confirm Each of these conditions exist and are entered properly.

If the contribution is in 2021, for 2020, remember the Conversion is for 2021.