Perhaps you could explain what you think is wrong more clearly
First of all never use Claire on poison phase. Only hellfire. I have never used Claire on poison and bleed phase unless I am playing against biohazard nodes.And yes that looks like a bug because buff immunity debuff means no buffs. I think it is just a one time bug it won't happen I call it a glitch.But still for tip never use Claire on bleed and poison phase unless you are going against biohazard. That fight would have been just 30 Sec long but you took it to 2 minutes that ended up costing you a revive.