It does not mean that you will get a W-2C, only that you might.
A 2020 executive order deferred the withholding of SS & Medicare tax because of COVID. That was an option that many employers did without informing employees that it was just a deferral.
Because SS & Medicare tax will make no difference to 99.9% of all tax payers - the W-2C (if it comes) can be ignored. Only if the additional tax exceeds the maximum yearly amounts would you possible get a small refund.
The e-mail is just to alert you to the possibility.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**