It's already bad enough that it's too damn tanky that sometimes people won't be able to guess which chest has the bonus THEN you proceed to punish people if they can't kill the chests by kamekaze-ing the whole team. I wouldn't mind if it was only a bit of damage, but there's a treasure stage with FIVE of this stupid chests that will kill your entire team if you don't deal with them. And THEY'RE TOO TANKY AS HELL.
Just don't let the damn treasure chest explode and proceed to kill the player's team. Just make the treasure stage a somewhat minigame to amuse players. If they don't guess properly then they don't get stuff. DONE and just straight to the boss stage. If I had an option, I couldn't care less about the treasure stage I would just skip to the boss stage and deal with the actual boss itself.
Either THAT or just remove the treasure stage, it's more of a hindrance rather being helpful. Players don't have to waste their cooldowns on a stupid chests stage, instead just throw them instantly to the boss stage and let them deal with the boss. My god so annoying.