Form 8889 Line 13 bug, not taking smaller value and incorrectly taking HSA deduction

[taxman26]

This year, my wife didn't fully fund her HSA contribution to help defray an overcontribution from the previous year. As a result, her Form 8889 has line 2 zero, but line 12 nonzero. TurboTax seems to be taking line 12 as line 13, with the net effect of my wife taking an HSA deduction. This seems extremely wrong, I'm pretty sure I can't take an HSA deduction just because I didn't contribute to my HSA.

The observed behavior is on TurboTax Desktop. My token number is 1094360

[dmertz]

What you described seems correct.  The amount of the excess HSA contribution for the previous year was not excluded from income that year, so applying it as part of her contribution for this year makes it deductible this year.  See the instructions for Form 8889 line 13 regarding "Deducting an Excess Contribution in a Later Year."

https://www.irs.gov/pub/irs-pdf/i8889.pdf