You are not paying tax on them and it is not deducting it from your refund or increasing the tax due. Turbo Tax started out by assuming you didn't get it and giving you credit for the whole amount so your refund was too high to begin with. Then when you entered what you already got the starting refund was reduced or the tax due increased to your real actual refund. Otherwise you would be getting the Stimulus amount again on your tax return.
Look at your return. The Stimulus payments do not show up anywhere as taxable income so you are not being taxed on it. And it's not being subtracted anywhere.
A common adjustment is if you claimed the Recovery rebate credit on 1040 line 30 when you already got the Stimulus payment or got the second one after you filed or reported the wrong amounts or entered the wrong amounts in the 2 boxes. If you entered the total you got for both rounds in the same box it would think you didn't get the other one.
