Blizzard has disabled Twilight Warding and Decay Augmentation Witchcraft Powers infor the time being, as they have been causing a bit more chaos than intended.
season 7 started on January 21, known as «Season of Witchcraft» and brought several new features along with it. Witchcraft Powers are a new seasonal mechanic that allows players to equip up to 6 powers at a time, similar to the Vampiric Powers fans saw in Season of Blood.
While these powers were meant to make players more powerful, it seems that two of them specifically were a bit overtuned, which allowed players to deal an intense amount of damage.
Blizzard released a statement via their forums to discuss the issue,stating that for now, the two powers in question will be disabled while they work on a fix. At the time of writing, Blizzard has yet to give a date for the return of the two Witchcraft Powers, but they do state that they are still purchasable in-game.
While the development team works on a fix for the over-tuning, they advise that players do not purchase the powers until they are enabled once again, as they will not be able to equip them nor will they receive them at this time.