You'll need to amend your 2023 tax return to make the correction on that tax return and you'll need to zero out the $6,500 of basis carried over to your 2024 tax return.
TurboTax used to have a selection to explicitly indicate a Roth conversion, but they eliminated that (at least in the desktop version) more than a few years ago, now requiring the slightly convoluted way of indicating a Roth conversion.
