I did a large hit that stunned Elsa with big baby (while she had fear), her glacier armor didn't activate. The next 3 hits on her (while she appeared to be at 1 health.) didn't do any damage. Is she supposed to be invincible at 1 health even if she doesn't activate glacier armor? Seems like a bug to me.
Edit: also, she never did activate it, came out of stun and my next attack killed her