Agree with the OP and the responder. I don’t know if it’s possible, but disabling the health during arena would be the best option.
couple of other issues I’ve noticed.
Evolutions:
When you go to Evolve a card (after using the instant upgrade within the hack) the game goes into a time-out and needs to be closed and reopened to continue. The evolution does not happen.
Hero Levels:
Heroes seem to level up to the max available level during their first level up, within the hacked version. If you open a linked account in an unhacked version, the level is defaulted back to the actual level.
So, when you go to unlock or upgrade hero skills, the game freezes again when you’re not actually at the required level, yet the hacked version is displaying a higher level.