[quote]It works; I finished it without a problem a couple of weeks ago.[/quote] Same. I finished mine in 5 weeks with no issues whatsoever. When the attack is successful, you clearly see an item pop up on the right side of the screen. You don't even have to stay until the boss dies. I have no idea why so many players are struggling with this.
Good for You, but I'm stuck from more than 5 weeks :/