Killing side bosses with rewards doesnt give me anything

Basically the bosses that provide a reward that are not from the main mission line don't seem to reward me. For example the boss located on the map “Freythorn” doesn't give me neither the 30 spirit to activate passives, nor the support skill gem. I've tried to kill him twice and he still doesn't give me anything. The process was as follows: I created a witch and due to a bad decision about the rise of some skills, I ended up making another one and for some reason this one doesn't receive rewards from some of the bosses like the one I mentioned.

Thanks for your time