Hi LifelessAtom,
When you trigger a Kill All event, what that does is destroy the particles that are currently in the scene. Expect the particles to continue to spawn if you uncheck Stop Spawning.
If you check Stop Spawning and you still see particles afterwards that is a bug and I wasn’t able to reproduce that issue since I was able to kill the particles and stop them from spawning.
I checked ribbon particles that were spawned via Spawn PerUnit as well.
,
Ed