Normal enemies with mods / monster effects

At Act 2, in Valley of the Titans map, some enemies triggered lightning damage surronding them (I believe is the Periodic Lightning Explosions mod) throughout the map. They were from normal packs, not minions, and seemed random when it was trigger, making dificult to even take a screenshot.

Bug id # 2.444.489.995

Another instance of something similar that could be related.

Bog Witch triggered massive amounts of cold explosions.