NAME: Ward of the north, Gifted Ice and Revenge damage reduction does not affect Shields.
DESCRIPTION:
Ward of the north, Gifted Ice, Shared Pain (Dreadnought) and Revenge are not reducing the damage taken by shields, only health, which I think is unintended, specially with ward of the north, dreadnought and armored tower being frost cards.
Other damage reduction effects like Life Weaving, Unholy Power, Unity (Frost), Green Peace (Frost), Gift of Resilience (Wheel fo Gifts) and Stone Shell work as intended, reducing the damage taken by the shields.
Revenge does not reduce or reflect damage taken by shields.
REPRODUCIBILITY: Always happens. To make it happen:
Summon an Avatar of Frost (or any nature unit + any shield spell in the case of green peace)
Let it get hit by a Bandit Walker in the Forge.
Do the same but with the mentioned spells affecting the avatar.
Notice how the shield takes the same amount of damage. then test with other mitigation spells and look how the shield takes less damage.
SCREENSHOT: https://freeimage.host/i/b7IJFS
ADDITIONAL INFORMATION: I am not sure if this has always been like this but I feel is not intended as it reduces the value of shields for pure Frost decks and other mitigation spells work as expected.