Bugged Buff Expiration - Ancestral Cry

Ancestral Cry is tagged as a "buff" in-game but its expiration doesn't get delayed by either Prolonged Assault/Lasting Boon's "Buff's Expire 10% Slower" or by Temporal Chain's "Effect Expiry Speed Reduction".

I suspect the Ancestral Cry effect is somehow misclassified in the game's code, as even Charges (which aren't buffs) are properly affected by Temporal Chains.