I came across this explanation from a lawyer:

• FDA approved a drug with label of Comirnaty.
• If it is not labeled Comirnaty, it is the experimental drug that is EUA still, not approved
• Pfizer is likely to try to get people to take the EUA drug, not the approved drug, due to liability
• Only real difference is the label (drug is exactly the same), but for Pfizer liability it's a huge difference
• Also, Congress trying to push a bill through that would protect Pfizer from lawsuits

https://survivaltricks.wordpress.com/2021/08/24/are-the-fda-and-pfizer-biontech-scamming-us-with-a-license-in-name-only-and-why-do-they-want-us-to-be-vaccinated-so-badly-aletho-news/

FDA's letter:

https://www.fda.gov/media/150386/download