First thing I should do is describe how I interpret what triggers secondary spell plague explosions (according to the pub notes). As I understand it, only spells should trigger secondary spell plague damage, and I believe the Devs said no other types of damage. I've been testing a few things since the publish, and I can say for certain that poison ticks can in fact trigger spell plague secondary explosions still. I also found that a pet cu sidhe can trigger secondary explosions as well. Cu Sidhe do not cast spells, but they do have a bleed attack, so I'm not sure if it was the melee damage or the bleed damage that was causing it, but spell plague damage was triggered in this manner. So, again maybe I'm misunderstanding how it's supposed to be working, but wasn't the change supposed to be that only spell damage triggers secondary spell plague explosions? Non-spell things that come to mind include damage over time and delayed damage things like poison, bleed, explosion & conflag potions, death strike, and of course the big one that I think was the root of this change, nerve strike damage. Haven't been able to test them all, but I wanted to understand the rule first before doing any more testing.