After running this quest 5 times i have finally gotten the optional to not count properly. but, i wasn't the one breaking them on the last run so i don't know where it went wrong (except that it was in the room with the 2 big exploding ones) and someone ddoor'd during the end fight to check for exploding barrels and couldn't find any. So something is weird with the chain reaction.
I ran this three times yesterday (really enjoyed it). I used fireball to blow up the barrels. Every barrel in the mission was destroyed but at the end I was still short anywhere from 11 to 18 barrels.
It appears that sometimes explosions are destroying them in a way that doesn't count towards the optional. I didn't think to check whether I got full credit for breakables when destroying the barrels.
I have run this one a number of times now, and have never missed the optional.. always using the chain reaction method. Dunno if I am lucky or not, but I have done this (literally) about a dozen times now (I love the crafted weapons.. a little too much heh) and have never had this occur to me before.. but that doesn't go without saying that it won't ever bug out on me, so I will keep doing what I am doing I guess.
I actually had the barrel by the shrine explode twice on me. I set it off using a chain reaction, and it went BOOM while I was a safe distance away. So then I figured I'd run up to it. It went BOOM again and killed me. I was going to try to reproduce the bug, but I had other things to do. =)
Going to sacrifice my rogue and see if meleeing the barrels vs shooting them makes a difference. she has +50 ish to saves so we will see hehe.
I have tested this room...ended up with 33 barrels left uncounted and all barrels broken. The problem seems to be that somehow barrels are not being credited if any mobs are in the area when the barrels are broken. I sneak or invis into the room and break the left and right chains to start. Then kill all mobs away from the remaining barrels. Once room is clear you should then be able to advance the optional to completion. This method has worked every time for me.
Some people are like Slinkies
They don't really have a purpose
But they still bring a smile to your face
When you push them down the stairs
Every solo run I've had in there has been fine. The only time I've had issues is when I'm with a group and spells were being tossed about.
Glenalth Woodwalke ■ Preston the Ranger ■ Brisqoe the Dentist ■ Prescription Liberator
AoK @ Argonnessen