@april30me Was the $600 on line 30? It should not be there. Line 30 is only if you didn't get the full amount for the first 2 stimulus checks or qualify for more. You did get the $600 so the IRS took it off your return because you tried to claim it again.
And that is just one of the generic reasons why they adjusted the Recovery Rebate Credit on your return. See this IRS article
https://www.irs.gov/newsroom/irs-letters-explain-why-some-2020-recovery-rebate-credits-are-different...
