Energy shield leech

Hi everyone. I have a hybrid build with petrified blood. Also i'm using selfcast ice nova+frostbolt. For the defence i decided to have an explicit mod for ring 'cold damage leech as life' and it work well. But now when i crafted extra life as es and speel damage leech as energy shield on my flask to recover both pool. BUT this an issue. Spell leech seems to doent's work. Even node on passive tree.
I remind you that life leech still working.
Can anybody explain me the situation?

The maximum total energy shield recovery from leech is capped at 10% of your maximum energy shield by default, so it is possible that you are leeching energy shield, but the amount is so small that you do not notice it.

As far as I can tell, there is nothing that should prevent your leech from recovering energy shield, it would simply take very long.