IRS indicated they received my 1040X form - tax period Dec 31, 2021 but can’t find the return. Never sent a 1040X for 2021, only for 2020. What is the issue?

The payment amount reported by the IRS matched the amount I calculated that I owed when submitting an amended 2020 tax year 1040x - this action was done 4/17/2022. But I never submitted a 2021 tax year amended form. So I am not sure what they are trying to convey when they claim they received it but now can’t find it.