It looks like a Mythic+ hotfix has gone out which fixes a prominent cheese strategy on the 2nd boss in Throne of the Tides and in Darkheart Thicket.
Throne of the Tides is the most dangerous dungeon and people were trying to speed up the dungeon any way possible. One of the tips was to dodge the Festering Shockwave cast on the 2nd boss using Line of Sight as seen in the following video.
However, this appears to have been hotfixed in the last hour. This solidly maintains Throne of the Tides as the hardest current dungeon. The other tip about the 3rd boss does still apply to our knowledge.
The bears in Darkheart Thicket are very deadly if they last too long, or the double bear pull. However, while the damage of the spell was 60 yards, the application of the debuff was only 30 yards.
Therefore, you could outrange the application of Maddening Roar preventing it from doing more and more damage.