BRD anniversary edition nerfed on LFR and normal, barely touched on heroic
All bosses have similar patchnotes
All bosses from the event raid got similar nerfs as seen above - HP pools lowered on normal, damage of many spells reduced on normal, sometimes LFR and barely on HC.
So raid should be easier to complete at least on normal and LFR, though on LFR it wasn't too hard anyway already. Unfortunately anyone who wants meaningful rewards from heroic will probably have to wait until more guilds try and fail that difficulty, as HP pools of bosses are still not matching the difficulty of the raid and some overlaps of spells are at least annoying and sometimes deadly.
Full patch notes
https://eu.forums.blizzard.com/en/wow/t/the-war-within-hotfixes-24-october/544737