You know that domain clients only pull Group Policy information if they have noticed a change in policy; otherwise, for the sake of efficiency, they skip over GPOs when they realize that nothing has changed inside that GPO since the last Group Policy refresh cycle. Part of the way that clients determine whether a GPO has changed is the version number. If the version numbers have not changed since the last GP refresh, the clients do not process GPOs during the refresh. But if they find a GPO that has updated version numbers since the last refresh, the GP refresh will reprocess the GPOs that apply to that workstation.