You stated this: "Based on filing status and income they qualified for this amount."

But this info would be for 2021, which isn't over yet. The EIP 3 is the same as the others, which means, issued based on a projection, based on prior years' filings. And then reconciled on the 2021 tax return.

If this is definitely a duplicate payment, it can be void and returned:

https://www.irs.gov/newsroom/economic-impact-payment-information-center-topic-i-returning-the-econom...