Trial of the Hermit Doesn't Unlock

Hello,

I've been having an issue unlocking this achievement. I've killed so many Great Bears that i lost count and i still can't unlock the achievement.

I read a thread about a guy having the same issue and 7 people got the same problem, no answers yet, so i decided to open another one.

I do have mods installed but are mostly retextures so i don't think the culprit is among them. I also restarted the trial with no effect.

Does it have to be me the one dealing the final blow?