Not sure if Blizzard is going to want to change this but, currently the buff from the daily quest at the peak of serenity stays on during raids. It always used to, but the mastery buff "enlightenment" used to be irrelevant because it was the same as the paladin mastery buff and they didn't stack.
Since that mastery buff has been removed, we now as a class have access to an 'external' buff to ourselves we can get which is something they should probably fix by having it removed by hitting a raid boss / dungeon boss. It also persists through death. I plan on stacking this buff every day (it stacks, i have 4 hrs+ on my alt already) until the xpac to level a little faster. [im also submitting this as a bug so u know]
TLDR; mastery buff from monk daily still applies and is now relevant because we no longer have the mastery buff available from any other source.
Edit; anyone else getting their SEF clones killed? think doomfire has been killing mine. Also they pull mobs if they run into range D;