Sirus loot (not Feared) barely dropping?

I did 15+ encounters and in fact did not drop one Thread of Hope which had a drop chance of approx. 55%. At this point I wonder if there was just a hidden loot table nerf or if in fact there is a bug coming from the Feared bug fix this league. I did witness Sirus by mistake.

I also did not drop a single unique from sirus yesterday. The fight was witnessed by maven and the kill was from my spectre with cull.

I always thought, that atleast one unique was guaranteed.