Tear of purity bug

Just finished my uber lab for the level 30 purity of elements on the new scion ascendancy and the increased reservation on it doesnt work. Ive tried my socketed version versus the new level 30 version from ascendancy and get the same reserverd mana left. Please help

This reservation efficiency applies to all Purity of Elements not just to one granted by the notable.

So how much mana it reserves?

to my understanding (correct me if im wrong)
100% reservation efficiency = cost reduced by half
so if purity costs 50% mana 100% reservation efficiency costs 25%

only with 100% reduced reservation would the skill cost be free?