You have various ways to resolve this issue.
First, if you are using TurboTax Desktop, you can use Forms Mode to view if you have 2 Form 1099-NEC. If there is the second 1099-NEC, you can delete it in Forms Mode and rerun Smart Check.
Another option you have is to look in Other Income for the duplicated income and delete it.
Otherwise you can enter the duplicated income as a negative number in Other Income as Adjustment to 1099-NEC income.