Gloom Leaf ability with entangle

Hi there,
I recently got Gloom Leaf from a chest and I was using his ability and noticed that he will not steal any attack from an enemy if it is entangled. I am not sure if this is intended. I understand that when an enemy is entangled it’s attack goes to 0 but still has its original attack once the entangle wears off. Also if Gloom Leaf is entangled himself then he will not steal any of the enemies damage while still reducing it.

Attack can’t be gained while Entangled, this is intended.