If the an amount contributed through your employer for 2021 (code W in box 12 of your 2021 Form W-2) is returned, the amount returned will also appear on line 8e. It needs to be taxed because your employer excluded the amount from box 1 of your W-2. Also, if TurboTax believes that you have an excess HSA contribution for 2021 (which would be the case if you have not yet completed the HSA section to indicate your eligibility for the contribution), that amount would also appear on line 8e.
