Is there an unannounced raid of Terrorsleep and Feversleep on North Roshamuul Surface?

Question

Guys, I dont know if It is something already known, but I have found a raid of terrorsleep and feversleep on Surface roshamuul on north. Not inside cistern, but on Surface, on normal spawn of retching horror and choking fear. I was hunting, i was there 1 minute before, with normal spawn of retching and choking fears, suddenly the place is infested with them. Like a lot. Do you guys have any information on this? Why, how they appear..?

Answer 1

It is an unannounced raid that occurs randomly. There is also a Silencer raid near the walls of Roshamuul.