what's happening on the rest of the 8606? Does line 8 show your 1099-R conversion, Line 13 should show the nontaxable amount and Line 14 is the basis left over, it's a calculated field not something you would or should adjust. If it's not zero that means something has not been entered or answered correctly across the 1099-R and IRA contribution sections so you should go back thru them.
https://ttlc.intuit.com/turbotax-support/en-us/help-article/retirement-benefits/enter-backdoor-roth-...
