Unable to use firetrap

I was fighting Nightmare of Catarina in the Ziggurat map when suddenly my firetrap skill became unusable after she summoned the first miniboss. The skill shows that it can be used (not greyed out), it works fine when I zone out, but when I zone back I'm unable to use it. All other skills (curses, shield charge, enduring cry, etc...) are usable. I don't have any specific debuff me either. I tried changing bindings, skill slot, but nothing fixes it.