Did you have an HSA last year? This is what Line 18 refers to.

If you didn't have an HSA either year, try the following:

The safest - although brute force - way to fix this is to 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

3. go to Tax Tools (on the left), and navigate to Tools->Delete a form

4. delete form(s) 8889-T, 8889-S (if one), and 1099-SA (if one)

5. go back and re-add your W-2(s), preferably adding them manually