There is a problem with the AoE damage on this fight. The Unstable Monstrosity that ticks every 4seconds only lasts 50seconds and the one which ticks every 3seconds lasts 70seconds.

http://img515.imageshack.us/img515/5875/ultrabug.png
1st report http://www.worldoflogs.com/reports/rt-lle55b0o3oc19hj6/details/120/?s=9400&e=9716
2nd report http://www.worldoflogs.com/reports/rt-wcfpqtasndets633/details/59/?s=3410&e=3668

These are just 2logs from our 10man normal. But I checked other guilds 25normal/heroic, 10heroic and even 25lfr. All versions of the fight show the same bug, 4sec Unstable Monstrosity only lasts 50seconds.

WoL could be wrong in 100% parses ofc but it's unlikely enough that I would like to know if this is a bug and if it's known.