yesterday i went to obsidian sanctum with my guildies doing it with one drake (tenebron)
this morning I was checking the wowwebstats and it seem that devouring plague hitted like 12 sartharion twiligth whelps and 8 lava blaze hitted tenebron 2 time and sartharion 9 times so 31 application over 7 minute 34
with the cooldown the figth would have needed to last over 12 minute
do anyone else can confirm this
possibility I think of are bug with the ineteraction with mind sear or bug with the DK spell pestillence