I found a purple crystal during a quest. I already had one in inventory, when the new one was identified. After the identification they both had same qualities, and the new one also lacked the same abilities as the old one. So either someone (npc monster) had already used the new unidentified one, or for some reason the script made it identical with the one I had in the inventory already.

Monsters can use them.

They can!

Sounds like this isn't a bug?

Allright, I was just wondering about the thing that both had similar amount of charges left.