Aura.GUID is zero in vanilla 1.12

IEnumerable<Aura> AuraList = ObjectManager.Me.GetAllBuff();
foreach (Aura aura in AuraList)
{
    List<ulong> list = ObjectManager.Me.BuffCastedByAll(aura.GetSpell.Name);
    Logging.Write(aura.GetSpell.Name + " GUID " + list[0] + " count " + list.Count);
}

output is below:

17:39:14 - Power Word: Fortitude GUID 0 count 1
17:39:14 - Inner Fire GUID 0 count 1
17:39:14 - Shadow Protection GUID 0 count 1