Resonating shield mana cost scaling

Did you forget this skill while fixing mana scaling for other skills? Why does it go through the roof with levels, even tho it is channeling skill, so you constantly drain it's mana.
What's even worse, it has some weird issue with leeching mana. Any other skill, even being mostly converted to other element, will almost instantly fill mana with a single mana leech affix on gear, while resonating shield cannot even leech enough mana to sustain itself while being purely physical.