So I found when I ran my titan on Sunbreaker, code of the siegebreaker, and equipped Polaris lance, if the burn or explosion from the perfect fifth perk deals the final blow to an enemy, it generates a sunspot. Sun warrior becomes active in the same sun spot and it only happens on when using the siegebreaker tree on the sunbreaker. Cauterize does not activate from it though and won’t activate from kills the sunspot makes either. I tried a whole bunch of other perks and gear that might activate assuming the game was treating perfect fifths explosion like a grenade or some other ability like trying to see if roaring flames or tempered metal would activate but neither seem to. Similarly, armor pieces like heart of inmost light doesn’t treat it as an ability kill like a grenade or melee either so this seems to be the only weird interaction I found. Not sure what should be done about it but it’s kinda quirky and makes the gun just [i]slightly[/i] more powerful which I like, but only when using one tree of one subclass so I think it’s very clearly a bug. Try it out and see for yourself though. It’s slightly tricky to make sure the perfect fifth explosion is the killing blow, but it activates every single time you do. Very consistent.