Raid Tuning and Nighthold Release Date
In the recent Q&A, it was mentioned that the next Q&A would be around Patch 7.1.5 release, maybe in the first couple of weeks of January. Patch 7.1.5 and Nighthold release dates are independent of each other.

Originally Posted by Blizzard (Blue Tracker / Official Forums)
As the holidays approach, we wanted to take a chance to share some information on an upcoming raid tuning adjustment as well as the release date for Nighthold.

Trial of Valor will see a set of tuning adjustments next week, focused mainly on Heroic and Mythic difficulty, which should help groups overcome the challenges of the Trial as they prepare for Nighthold.

Which brings us to the release date for Nighthold itself: We are aiming to unlock Normal and Heroic Nighthold on January 17, 2017. Raid Finder wings and Mythic difficulty will release during the weeks following, which we will share more specific details on at a later time.

We look forward to seeing you in the Nighthold!

Prestige Bug

Originally Posted by Blizzard (Blue Tracker / Official Forums)
Thanks for bringing this to our attention. There was a bug with players who reached Honor Level 50, Prestige Level 4 where honor earned was still being accumulated past the cap. When the Prestige Level was increased yesterday, the accumulated honor was applied and the character progressed through those new Prestige Levels.

The rewards were legitimately earned through playtime, however, so we won’t be removing them. This bug should be fixed in 7.1.5, so that others in similar situations will earn those rewards immediately, and so that this will not affect future seasons.