Why don't my 2024 HSA contributions show up as a tax break; this year they did. Box 12W shows my contributions as employer contribution but it was my payroll deduction?

Amounts shown on your W-2 in box 12 with code W can be your contributions from your paycheck, or contributions made by your employer.  There is no distinction between the two values if you both contributed.  Either way, the contribution was made through your company's payroll system.  

When the money was taken out of your paycheck for deposit into your Health Savings Account (HSA), it was done with pre-tax money.  Therefore, you have already received the tax benefit from making that contribution.  

If you were to make an additional contribution to the HSA outside of the payroll deduction, then that would be after-tax funds and the amount would be shown on your tax return as a deduction.  

Your employer has already reduced the amount that would otherwise be in box 1 of your W-2 by the amount reported with code W in box 12.  You don't get to deduct that amount a second time when preparing your tax return.

This is NOT correct. I recalculated the taxes using the IRS tables and the result indicates the HSA amount from code W is not deducted from taxable income. As it stands right now on TurboTax, the AGI does not change whether you have a W amount or not.

@ReTi the HSA contribution is already deducted from Box 1 of the W-2.   Go back and look at your December paystub and compare to Box 1 of the W-2.