Remove unwanted prefix from sender's email in Mail?

Mac Mail - delete prefix added before my email address. Came from someone's address list?? Example:

FROM: MY Friends <jimc@xyz.xyz>

The string "MY Friends" came from somewhere and I see it in Sent Mail and replies. I tried to search in Mail and it was not found.

It's not hurting anything but it's a big annoyance. How to turn it OFF please.