Your idea of the mechanics is wrong.
Sanctuary adds a damage percentage, exactly like the 50% bonus for blunt weapons against Undead. This extra Physical Damage percentage varies in amount by your character's skill* level.
Sanctuary also adds a Magic Damage 'area pulse' that simply applies a Magic Damage figure to Undead within it's effect radius.
I just checked it and the area pulse is working fine. Note however that the Magic Damage pulse does almost nothing with a sLvl 20 skill in Act 1 Hell
*edit: left out the word "skill" . . . yikes :o
Sanctuary adds a damage percentage, exactly like the 50% bonus for blunt weapons against Undead. This extra Physical Damage percentage varies in amount by your character's skill* level.
Sanctuary also adds a Magic Damage 'area pulse' that simply applies a Magic Damage figure to Undead within it's effect radius.
I just checked it and the area pulse is working fine. Note however that the Magic Damage pulse does almost nothing with a sLvl 20 skill in Act 1 Hell
*edit: left out the word "skill" . . . yikes :o
Heed the Song of Battle and Unsheath the Blades of War