I agree, you do not claim the credit twice.  That is not what form 5884-A does on an amended return.  Actually, somewhat the opposite.  5884-A is used to show the credit received.  Then that credit flows through to the front of the 1120S, 1120, 1065, etc. to reduce the payroll expense deduction taken on the original return.

Much like the employee tip credit, you either take the credit or the deduction, but not both.  Once you receive the credit from amending the 941's for 2020, you must then use the 5884-A on the amended income tax return to reflect the credits and reduce the total wages originally deducted.

Hope this helps clarify.  Intuit just confirmed they are working on this change for the form 5884-A to deal with the three different ERC's we now have.  (One for disasters 40%, one for 2020 Covid wages 50% and one for 2021 Covid wages 70%.)