My tax-free contributions to my 2024 HSA ($2,596 -- well below the limit) are being classified as "taxable employer contributions." There's no way to edit. How to fix?

First, this means that you code W amounts in box 12 on your W-2 was $2,596, right?

 

Second, it is likely that you did not go through the HSA interview to show that you had the correct HDHP coverage to justify this contribution.

 

To go through the HSA interview, please navigate to Deductions & Credits->Medical->1099-SA, HSA, MSA and make sure you go call the way until you see the HSA Summary.

 

Once you finish this interview, you will find that this amount is now under "tax-free employer contributions".