It depends on what happened in 2019. Did you actually do the Roth conversion in calendar year 2019 or did you do it between January 1 and July 15, 2020 and count the contribution as a 2019 contribution?
If you did it after the end of calendar year 2019, your basis reported on your 2019 return in your traditional IRA would be $6,000. If you made another contribution in 2020 and converted both within 2020, your 8606 for 2020 would have 0 as the ending basis on Line 14 but 6,000 as the beginning basis on Line 2.
You can face a fine of $100 for over reporting your basis in your IRA, but I don't think that's what happened here. It looks like due to the timing differences between year-end and the contribution deadline, you did have some basis reported at the end of 2019.
If you have a starting basis reported on Form 8606 for 2021 but did not make your 2020 conversion in 2021, then you did report something wrong in 2019 or 2020.
