If it is correctly calculating the CTC (and it's lame to charge for one to confirm), then it's very poor and misleading UI (see Deductions & Credits > Advance payments, Child and Other Dependent Tax Credits). If you enter the AdvCTC from 6419 into TurboTax, then it should display both CTC amounts for 2021: (1) AdvCTC, and (2) the rest of the credit you're owed. As is, TurboTax online only shows in the UI what you entered from 6419. And if you've filed previously with TT, then the 2021 CTC likely shows a lower amount than 2020 when in most cases, your CTC should be more (unless your AGI is significantly higher or # of dependents less/different).
