did you key in your contribution twice? (which is the mistake most make).
it's already in your W-2 and that is all that is required, unless you actually sent a check to the HSA firm.
Code W of box 12 of your W-2 reflects the 'employer contribution' which is a misnomer because it reflects what your employer withheld from your payment PLUS whatever they kicked in.
the 'employee' contribution is what you sent to the HSA firm OUTSIDE YOUR PAYCHECK and I suspect that is the duplicate in this situation
