Aren't Leggo Memories 100% Chance to drop in Torghast?

I’ve solo’d Mortregar Layer 3 and 4 just now and did not get the Bryandor’s Might legendary for my Death Knight. I solo’d it in blood spec, with blood as my loot specialization. Is this a bug or is it not 100% chance to drop? Coulda sworn it was.

Hey there, you can get 2 of them per week if I am not mistaken. Here is also another post about the drops Legendary Post