It seems a previous buff to Mage’s Frostfire Hero tree has been reverted in patch 11.0.7.
Players have been noticing a buff that was applied in the November 26th class tuning pass has suddenly gone back to pre-buff status as of the new patch. Su_Xin noticed that the 
Excess Frost cooldown reduction to 
Comet Storm/
Meteor has gone back to 5 seconds, when it was buffed to 10 in the tuning pass. There was no mention of the change in the 11.0.7 class tuning notes.
The question now remains whether this was an intended nerf/reversion or if it’s a bug that needs to be fixed.