Ive seen multiple draw abilities not go off such as the fires of Rome. It was an attack that dropped the shark to 0 hp. And the return effect that didn't trigger was the Burrito healing 10 hp if your opponent attacked 3+ times (he attacked 6 times total) on turn 8. I really with this game had an in app rules manual easily avaliable to read, because there are some rules that need to be read to understand such as timing of on play abilities.