If you search the Global Catalog and notice that some attribute values aren’t populated in the Summary Results page of PeopleSearch or PeopleUpdate, it’s likely because the attributes are not replicated in the Global Catalog that you are searching.
You can change the attributes that replicate to the Global Catalog using the articles below. Refer to the Active Directory schema Global Attributes list (https://msdn.microsoft.com/en-us/library/ms675094(v=vs.85).aspx) for a list of Global Attributes for different versions of Active Directory. You can also check the “In Global Catalog” value for an individual attribute to see if it’s replicated in the Global Catalog.
- How to Modify Attributes That Replicate to the Global Catalog: http://support.microsoft.com/kb/248717
- Global Attributes in Active Directory: https://msdn.microsoft.com/en-us/library/ms675094(v=vs.85).aspx