Not sure if this is a bug or working as intended, it seems like a bit of an oversight tbh. If it is working as intended please reconsider your stance on the issue. Anyway:

Fingers of Frost charges are being consumed by Molten Armor damage procs.

This means that if you have Molten Armor active and Fingers of Frost procs, and you have any melee/melee pet class beating on you, you're lucky if you can even get one instant spell out of the proc, which greatly reduces the versatility of the talent.

If you believe you have found a bug, or are unsure, please contact a GM in-game. Thank you.