What likely happened is that you on a previous pass had an excess contribution that you agreed to withdraw (this is what Line 12b is), but after you fixed whatever caused the excess, this value was retained by TurboTax.
The safest way to fix this is to delete all your HSA information and start the HSA section over again. Please do the following:
1. make
a copy of your W-2(s) (if you don't have the paper copies)
2.
delete your W-2(s) (use the garbage can icon next to the W-2(s) on the Income
screen
*** Desktop***
3. go to View (at the top), choose
Forms, and select the desired form. Note the Delete Form button at the bottom
of the screen.
*** Online ***
3. go to Tax Tools (on the left), and
navigate to Tools->Delete a form
4.
delete form(s) 1099-SA (if one), 8889-T, and 8889-S (if one)
5. go
back and re-add your W-2(s), preferably adding them manually
6. go
back and redo the entire HSA interview.