I ran up on the Black Morass Harrowstorm and the storm is churning and lighting and stuff, but no mob spawns, no tendril things, ain't nothin yeehawin here.
Others said they had 2 or more Harrowstorms bug out.
TKOEF1112
PC/NA, XBOX/NA
Bladestorm EliteA certified lizard, iberophile, and cheesemonger