In order to support auto-complete, Zimbra adds contact information for contacts you have e-mailed. Occasionally this results in an e-mail address incorrectly associating with a contact. For example: if Mary Dyer shared a Box file with you and you responded to that e-mail, all e-mails from Box about shared files show as being from Mary Dyer. This can also cause complications when someone is using an alias, it might mean that all e-mails from firstname.lastname@example.org show as being from “Mary Dyer” instead of more generically from “quakers.”
In order to resolve this, search your Zimbra contacts (mostly likely it will be in the "Emailed Contacts" folder) for a contact with that e-mail address (e.g. email@example.com).
You should find one (or more) contact associated with that e-mail (e.g. “quakers” or “Mary Dyer”). Delete the local contact and when you receive an e-mail from that contact, it should start displaying with whatever name is being used with the new persona (the Zimbra page might have to be reloaded).