So does this work correctly for dots? Everytime I see it proc, it just double attacks on the initial hit. Shouldn't it increase the number of ticks of the spell?
Working as intended I'm afraid. Also the double-attack is not affected by Ability Modifier either. In other words Spell Double Attack is pretty much wasted on Necros.
Is it really working as intended? This is from Time Warp: Time Warp allows the target to have their spells double attack for five seconds along with increasing the amount of triggers and ticks of their spells.