Firstly, I trust because all Teams devices (PC, Deskphone, Mobile phone) are all having the same issue, that this belongs in this server SE site, and not Superuser.
We are having an issue where an outside caller (the main company line, dialing employee's direct company numbers via a different carrier) displays different names on all Teams devices, for 3 users, when the same outside number dials in. The name displayed doesn't change per person called, through each of the tests. We have tried/checked, but all failed to resolve:
Verified the users names who are being displayed, incorrectly, in association with the main company line, don't have that number stored in on-prem AD, or Azure AD properties
Verified that they don't have any Outlook contact cards with that incorrect person's name and number stored.
Verified that they don't have any Teams contacts with that incorrect person's name and number stored.
Signed out of teams, and signed back in.
Cleared the Teams cache (%appdata%\Microsoft\Teams - delete all contents of folder).
Where else could Teams be looking for to match this name? At least one other user shows just the number (desired).
