What you were expecting to happen, and what actually happened?
Matched yellow gems with Knight Coronet, who had 9/12 mana, expected to get 3 mana. Instead, stayed at 9/12 mana. Different battle (my team was the same as in the first instance), Emperor Khorvash matches skulls against my Knight Coronet, who has full armour and life. I expected to take damage, but my turn started and my Knight was untouched. This occurred during PvP matches.
EDIT: Just had a Manticore with a 28 attack do 28 damage to my Knight Coronet with Stoneskin on a three skull match. What gives?!
Will update if more happens.