plague nova missing

i'm having an error where plague nova, the part of the plague bearer skill that allows the poison to be released once built up, is missing.

originally, I was having the error where plague bearer in general didn't unequip from my hotbar after being unequipped/getting the 'not enough spirit' error despite having enough spirit.

I unequipped all of my skills and reequipped just plague bearer, and now don't have the option to add it to the hot bar at all, even with the skill enabled on both weapon sets. I also no longer have the tab under plague bearer for plague nova, the actual skill, and if I try to alt/hover over (or click) plague nova in the skill description of plague bearer, the screen just briefly freezes and then continues as it was. it's almost like plague nova doesn't exist anymore?

screenshot shows the problem very clearly.

update: tried equipping wind dancer instead. greyed out plague bearer is back as a hot bar option while not being equipped.