Baldur's Gate : The Sword Coast Chronicles : NWN2 Persistent World

Warding of the spirits should ward shaman and allies alike. It does not.

It does not confer the bonuses it should to even the shaman when cast.

It's precised on the feat itsef that its effects won't stack for the shamans because they have "Blessings of the spirits" already, also it works but the bonuses are -only- against spirits.