I've been trying for weeks to get this exotic, I feel like it is the only exotic properly geared towards my Sunsinger currently in game, seeing as I typically use Fusion Grenades meaning I will not benefit from Sunbreakers. However, Xur has not sold it once, instead repeatedly selling mostly Voidfang Vestments and Sunbreakers. Meanwhile, I have been unsuccessful in acquiring it from raids and strikes, and believe many other Sunsinger-based warlocks have the same issues. Vote: Bungie, can Xur please give us the Heart of Praxic Fire this week? :)