Just did a run through Malchor’s Leap for resources and ran into some abnormally huge mob spawns. A couple spots in different parts of the map were spawning like 10-15 risen every three or four seconds. They were merging and stacking like the old bug with the jades in Ember Bay; hitting one revealed 10+ stacked under it. Another oddity was that it seemed that none of them dropped any form of loot. Could still use it to farm a boatload of exp if one needed it.
There were no events going on at the time and the meta info window said everything was concluded at the time. Dunno if the bug was a one time thing or if it’s happening in other instances.