S-corporation received ERC refunds in 2023 and 2024 relating to tax year 2021.  S-corporation 2021 amended tax return was paper filed and sent to the client in February 2025 who held onto it until end of September 2025. (Lacerte could not e-file as it was too old.)  5 out of the 6 shareholders received a letter and a refund check stating that the tax year was closed and they could not accept the taxes.  The 6th shareholder received a refund but not a letter stating that the tax year was closed.  He assumed his letter was lost in the mail and cashed the refund check.  The S-corporation was planning to amend the 2023 and 2024 tax returns since those were the tax years the ERC refunds were received.  But then the 6th shareholder received a tax notice stating that he owed the tax plus penalties and interest.  The IRS said he should not have cashed the check and he would need to pay it back.  If this is the case where the 6th shareholder pays the tax in 2021, how can the s-corporation amend the 2023 and 2024 tax returns excluding the 6th shareholder who had already paid the tax in 2021?  What can be done regarding the mismatch in the filing and not have the 6th shareholder pay twice?