Chance for FLASKS you use not consume Charges doesn't work with Concoction

So, the concoction skill says "Consume charges from your Mana Flask to throw a bottle that explodes...", and the passive Savouring says "20% chance for Flasks you use to not consume Charges".

Also, the chest piece called Husk of Dreams Shaman Mantle, have a effect "50% chance for Flasks you use to not consume Charges". But neither those effects are working with Concoction. Is this just a typo error, or it is really bugged?

Thanks.

When charges are consumed by concoction skills, you're not using the flask, so effects that give you a chance for Flasks you use to not consume Charges won't affect concoction skills, since you never use your flask - it just consumes charges from the flasks.

So why does my mail belt with the text "x% reduced flask charges used" affects the concoction skill?

I just wanna be sure i am understanding how it works so i can commit to the build.

It probably should work or they should reword it, but chances are that implementation just isn't implemented yet. Seems like the way it was coded is not actually part of how charges are consumed and it'll likely have to get added to the skill if you have that passive.