Found a Bug please do fix

Greetings.
I have found a bug there anoyeds me.
I am playing a Warlock deck
Where is use (Hemet, Jungle Hunter) -
Battlecry: Destroy all cards in your deck that cost (3) or less
And (Furnace Fuel) - When this is Played, discared or destroyed draw 2 cards.

It simply do not work as intended. And it kind of hampers my deck. Please do fix, would be lovely

I guess if the Furnace fuel dont work, the sludge do not either. Cant confirm this but i got my suspensions.

Best regards from the Warlock