Purity of Elements 100% reservation

Hello,

Something strange is happening. I bought the Purity of Elements gem (which says "50% mana reservation"); then I equip it (the gem still says 50%); THEN when to activate the skill, it says "100% reservation" and takes all my mana away.

I do not know what's happening :> Please help.

https://ibb.co/6gsy5ZF
https://ibb.co/6YmP2yt
https://ibb.co/WfZYdNg

U have linked the Aura to a Support Gem that increases it's Mana reservation costs. (Looks like second wind?)

lol

Thank you. It works just fine now.