I received a CP12 notice that the IRS had reduced my refund from $2806 to $2207, or $599 less. I was not surprisingly shocked that TurboTax had made an error!
Even more shocking was the fact that Intuit carefully shields its "Maximum refund, guaranteed" claim with legal gobbledygook that, of course, protects Intuit from any errors on its part unless you use their CPA service. That, of course, is not the point when you use TurboTax.
Did you have $600 on 1040 line 30? That is probably for the second stimulus check. Did you get it after you filed? A common adjustment is if you claimed the Recovery Rebate Credit on 1040 line 30 when you already got the Stimulus payments or got the second one after you filed or reported the wrong amounts. And you had to report the right amount in each box. If you put the total in 1 box it would give you the other amount again. The IRS knows they already sent it to you. Line 30 is only if you qualify more.