This one has got me stumped, can't find anything online about it. So basically, I have a user, uses Outlook 2019 but this happened previously when she was using Outlook 2010 also, Exchange 2013, Active Directory, Windows 10 environment. When she views certain contacts, the contact info shown in the display window is different than the contact she has selected. The example I've attached shows a contact for Vincent Pocino, it shows his email and office number, but on the right it shows the name Tom Hienze. Sometimes when she sends email to people, it shows the name of someone in her contact list, but the email went to someone in the Global Address List. I attached another example of this, Sent To shows a Tom Hartman (a Contact) but when you click on the name, it shows the actual person it went to, Maureen (another Exchange User in the Domain).
I can export her Contacts to a .PST file, open it, and they look normal, even in her own Outlook. I deleted all of her contacts and re-imported them from the normal looking .PST file, and they're all jacked up again.
I had her change her Contacts View to Address Card or Business Card and they all appear to be fine. I don't know yet if this will have any affect on her sending an email to one person and a totally different person showing up in the Sent field.
Is she seeing the same issue in Office online? portal.office.com? please be sure that the address book is updated and as a test, you can take the user out of cached mode and see if that makes a difference. Another test would be to see which release version is she on, have her try semi-annual as it happens to be a more stable release.
@Ash365 This is not Office365, just Office 2019 Pro Plus Install. But yes, the contacts do look the same (wrong) when logged in to Exchange through the Outlook Web App so that makes me think that cached mode would have no effect but I could try it.