Im very dissappointed as well, i did the karka boss and game crashed, no reward and no chest for me, this happend for many others. I was really mad after this happend.
i want my reward for this event, i also want to add i arrived at the last Battle of the event, right before lava killed the karka boss when the game crashed, so i wonder if my claim is legit or not, i had 10 dc this weekend as well. so im annoyed about that too.