Blizzard announced they’re simplifying the 
Authority of Storms enchant before the War Within to make it a more consistent option.
The damage will occur immediately when the enchant activates now and the tooltip will be updated in a future patch to reflect the change.
Before the launch of The War Within, we’re simplifying the Authority of Storms enchant to make it a more consistent option.
The damage will now occur immediately when the enchant activates, rather than granting you a buff which provides a window to trigger the damage multiple times.
We’ll update the tooltip in a future patch.