Failing bounty missions because mobs dont spawn

[Paradoxoglanis]

This was an issue when i played years ago, and it is still exactly the same. Mobs dont spawn in some missions, and if the missions are timed then they fail. Im guessing its because of the stupid way mobs spawn, where if one wave/group isnt completely defeated, the next wont spawn. I dont know if its just buggy code or if sometimes something spawns under the map, but it happens pretty often.

Ive noticed this when playing solo in PoE and Orb Vallis. I havent tried much of Cambion yet.