Outlook/Office 365 loads wrong display name on To: field.

I found our issue. We have a hybrid exchange on prem and O365 email server. And email contacts are the place that was getting other names on the contact card in email. It was a head scratcher for sure. If the contact you try to email shows the wrong name. Check for any other email aliases on the users mailbox. See example.  This is a Sales Mgr, and when Sales folks left his department, we would add aliases in case current deals wear being emailed to ex-employee and mgr can take the sale and continue the process. We removed the Alias of the oldest employee been over 30 days. And this started to show properly again after a forced sync.