Companion Invulnerability Aura

I have a companion that should be casting Invulnerability aura. Sometimes when I don't need it versus trash mobs it will cast the skill quite often with little cooldown in between (I have a CD reduction support). Then there are times I go like a whole minute without it casting the buff, often on a boss fight when I could really use it! It is working like either feast or famine. I am watching the pet to see if it is dying, but I don't think that is the issue.

Nah this thing is OP as is tbh, can we not bring attention to it please, they seem itching for nerfs and killing fun recently.