Dungeon Run: Greedy Pickaxe will drain a mana crystal if you attack while at 10 mana

[Jetz72]

https://us.forums.blizzard.com/en/hearthstone/t/greedy-pickaxe-prog-code-broken/9956

Card’s in-game coded mechanic seems broken “After your hero attacks, gain an empty Mana Crystal” Issue is once your hero attacks with this weapon equipped, it burns a mana crystal as well, meaning when you have 10 filled mana crystals, you attack with this already equipped from your last turn, you end up with 9 filled mana crystals.

Tested and confirmed:

Also affects temp mana:

Presumably it's implemented in a way that gives you a (full) mana crystal, then drains one mana.