Evoker Efficiency and generous gems - 0.9.5 Win10

Currently, the ethereal copies created by generous gems (the ethereal ones with only one charge) cannot be multicasted if you have a maxed evoker, even though the Efficiency perk description might lead you to believe otherwise.

But I’m also not 100% sure if it’s a bug or just an unfavorable interaction, in which gems don’t care about efficiency when they go from 1 to 0 charges. I’d really appreciate clarification if it was intended.