This might not be a bug, it is meant to spawn different Storm Generator levels - with some harder than others. Plus permits players to find generators more easily
Can confirm in 1.21.8.
Now i think about it, it is maybe the wiki which is wrong about it, i can't find from where the info that up to 4 sounds can be streamed simultaneously comes from.
No, i forgot to mention. This bug affects only stream. However this is observed even with two instances of the sound played at the same time. I'll attach to the bug tests RP & DP.
Can confirm in 1.19.4, Note that it creates a ghost item
After more exploration, i can confirm that chests are also affected, since SW.LootActor.StorminatorChest.Hard guarentees 2 items in the chest, which is not observed in game.
Same observations for the souls storm final chest, via SW.LootActor.StorminatorChest.Final.Low .Medium and .Hard (respectively 2, 3 and 4 items), can confirm that only the Low reward is looted out.
PS: would be nice if we could have some precisions about how the storm score is tracked/which level the final chest gets since this function is currently in the encrypted part of the game 🙂