One common thing a number of folks are experiencing if they claimed a Recovery Rebate Credit on their return for a stimulus payment (1 and 2) they had actually already received , or if they received a stimulus payment (1 and 2) after filing. Or if the IRS adjusted the amount of that credit for some other reason.
You can tell if you claimed a Recovery Rebate Credit by looking at Line 30 of your Form 1040.
Also check the IRS "Where's My Refund" tool. Sometimes there is a message there when they make a change, such as an offset.
https://www.irs.gov/refunds
Also, if you are expecting a state refund, it comes separately. So don't go by any total refund amount that is a sum of Federal and state refunds added together. TurboTax provides a summary figure that can be confusing. For the Federal refund amount you submitted, go by what is on your Form 1040, Line 35a.
