Symptoms

When executing the "Find User Groups" method on the "UMGroup" SMO and specifying the K2ADFS security label, it sees all groups except for the users "primary group" in AD. In this case the "domain users" group.
 

Diagnoses

This has been caught with the "Domain User" group, but after some investigation we found that it will happen with any group that has been makes as the user's "Primary Group" in AD. Example... If you set "Domain Admins" as the "Primary Group" in AD, "Domain Users" will be available, but "Domain Admins" will be missing.
 

Resolution

This has been diagnosed as a bug. We applied a cold-fix that LABS sent us on the environment and that fixed the issue. If you run into this problem, please contact K2 support for the fix.