I just had to redo a return (fortunately before it was filed) to show direct contributions in addition to employer funding.  Clients had more medical expenses than they had money in the account, and were smart enough to know that adding funds and then using them to pay the bills would save taxes.  They didn't communicate what happened as well as they needed to help me spot something unusual, but it got fixed.  Turned out they had gone over the $7,100 limit, so they had to call the HSA bank and recharacterize 2020 deposits to 2021.