New Recruiters not in Ownership Lists

Summary

New Recruiters Missing from Ownership Lookup Lists

Content

Every once in a while (more often than I'd like) we are running into new hires of Recruiters or HRG's that aren't showing up in the lookup lists available in the Ownership section, for example.  Does anyone else have this problem?  They are people with access to the system and user accounts with the correct User Types, but for some reason they aren't appearing in the lists. 

These aren't lists that are manually updated so I'm at a loss as to what the issue is and in the past I've escalated it to another IT resource that comes back telling me "it's fixed" but never explains or expands on that.  I'd really like to understand what the issue is.