When you spec for Everlasting Magic in the mages guild line, these abilities get their duration increased but do not get the damage of the DoTs increased effectively nerfing your own damage since you are doing the same amount of damage over a longer period of time. DoTs are already generally weak in this game, considering how many abilities can instantly burst for the amount of damage you'll get from a DoT in 14 seconds, they are especially weak in PVP and losing damage on them because of increasing the duration is a terrible mechanic so I assume it's an overlooked bug.
Edited by Mange on 15 April 2014 01:19