Wearing my Mara’s amulet (this is the 30 ar version)…I have 25% crushing blow and 0% deadly strike (I have 75% and 45, respectively, on this barbarian) listed on the advanced stats screen
TAKING Mara’s off, and wearing ANY other amulet, I have 75% crushing blow and 45% deadly strike listed in the advanced stats screen
My uneducated conclusion? It seems that this Mara’s Amulet is masking/negating offhand bonuses.