Don't remember seeing this in any of the previous patch notes.
The Bastion of Twilight
Halfus Wyrmbreaker
Shadow Nova is now cast less frequently in 10-player modes to account for fewer available interrupts there.
The captured drakes in this encounter now apply Dragon's Vengeance when they are killed instead of when they are freed. To account for this change, the health and damage of the drakes has been reduced, and the damage bonus gained from Dragon's Vengeance has been increased.
Depending on the damage output and health of the drakes it may now be viable to use a normal raid group on this encounter in heroic mode. Does anyone see the need to bring disc priests anymore? I wonder what the debuff will be after you kill one as it says its been increased....hrmmmmm