HSA reporting is different. HSA contributions made by your employer under a cafeteria plan apply toward your overall HSA contribution limit, so they need to be reported to you and the IRS and must appear on Form 8889 of your tax return (which TurboTax does for you upon entry of the code W amount on TurboTax's W-2 form). On the other hand, permissible employer matching contributions to your 401(k) are not reportable anywhere on your tax return, so they are not be included in box 12 of your W-2. Only your elective deferrals form your pay appear in box 12 with code D so that the IRS knows why your box 1 amount differs from your box 5 amount and so that you can claim a Retirement Savings Contributions Credit on Form 8880 of your tax return if you qualify.
