Enemies that trigger attacks when hit

Playing through Act 1 again on a plant spellcaster Druid, and noticing an overly punishing interaction: the Eternal Knights launch projectiles when hit, and Entangle creates fissures that hit them about 3 times a second. It isn't immediately obvious that these hits are triggering the projectiles, because as soon as the fissure is made, the knights enter a state of seemingly endlessly launching an overwhelming number of projectiles. The damage of each projectile isn't a problem, but at that frequency it adds up fast, which makes for a strange build-dependent difficulty spike very early in the game.

Enemies triggering attacks when hit isn't necessarily a problem, but those attacks could really use a cooldown so they don't get too carried away against skills that hit very fast.

They do that only vs ranged attacks. Melee is safe.

Just get into melee range and attack when he is swinging at you - he won't reflect during that animation.

PS. You should at least try to figure stuff out before asking to make it easier. Skill issue.