Active Directory contacts can be indexed by the Skype for Business (Lync) address book so they can be search by users. I have noticed some inconsistency in how the Skype for Business Contact Card displays these. For example:
- Contact display name is a phone number
- Search results show a phone number rather than display name
- Some numbers do not show up at all
- IM address displayed as a phone number
Microsoft are aware of this issue, however it was supposed to be resolved in the July 2015 client updates. My testing has shown that this is not the case. The only improvement I could find is that the display name is now correct in search results, but still appears as a phone number in the contact card.
You can work around this issue by adding an IM address for all your contacts. This can be achieved by populating the contacts msRTCSIP-PrimaryUserAddress address with a false SIP address: