I can confirm that the quest drops when breaking the head of an enraged bloodshot shroud. One page on the wiki does incorrectly report that the Gnasher drops the quest. Unfortunately I can also confirm that the bug still exists that doesn't allow you to complete the second part of the quest -- slaying 4 Heroic Razorwing Kharabaks. I slayed one with chain blades and it didn't register. This same bug has existed for many of the other blazeworks rumors so I'm not going to do a lot of experimenting.
Hi Coral_Fishman - I've been testing here and it looks like this quest does progress if you slay a Razorwing Kharabak on Blazeworks correctly (and x2 with chain blades). It doesn't need to be a Heroic, and I'm gonna get that objective updated for a future patch.