I could regenerate Energy Shield on a no regen map

I was in a map to fight Veritania, and Zana randomly spawned on the map.
I got an Elder Guardian map (Constrictor) with a 'Players cannot regenerate life, mana or energy shield' modifier, but for some reason I could regen Energy Shield without a problem on the map.



I popped Blood Rage here to get rid of my ES and didn't move or hit anything (I don't even have ES leech either)





Is this a bug, or am I missing something?

You can still recharge Energy Shield, it is only Energy Shield regeneration that would be prevented.