The IRS does not catch every mistake---but they do catch some of them. That is why we advise people to wait until their original return has been fully processed before sending in an amended return. It causes too much confusion for user and for the IRS if you put two returns into the system at the same time. And... it is currently taking the IRS about six months to process amended returns. If you complicate matters by putting an amended return into the system while they are still working on your original return, the delay can be even longer.
The IRS will likely send the OP a letter explaining the change....but those letters are usually mailed out several weeks after the change has been made.
If you received a late 1099R, please wait for the IRS to process your first return. Those 1099R's are reported to the IRS, and the IRS might catch it---or they might not. When your first return has been processed, if you still need to amend, you can prepare a Form 1040X. A 2021 Form 1040X can be e-filed.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
