When Blizzard implemented the PvP healing debuff in patch 3.3.2, they said that they would be monitoring the situation and will be making any adjustments they see fit. This debuff decreases all healing in Wintergrasp, Battlegrounds and Arenas by 10% and was a complementary change to the that made for the effectiveness of resilience.
When Blizzard announced this PvP healing debuff they mentioned that all shield effects would not be affected. Well they’re turning that stance around now with a change that seems to already have been hotfixed in. According to CM Zarhym, the PvP healing debuff will also reduce the effects of the paladin spell Sacred Shield and the Priest spell Power Word: Shield by 10% for Wintergrasp, Battlegrounds and Arenas. As always they will be monitoring the effects of this latest change.