Niagara Death Event spawns double particle on last event

Hi !
I was experimenting with Niagara and death events when I noticed an unexpected behavior.
I’m using Unreal 5.3.2 but I also tried on Unreal 5.4.4.

I have two emitters, one with the death event and another one with the event handler. The first emitter spawns a finite amount of particles and the second emitter spawn one particle when one particle of the first emitter dies. Nothing fancy.

I noticed that when the last particle of the first emitter dies, the second emitter spawns 2 particles instead of one. And It only happens with the last particle of the first emitter.

Steps to reproduce :

  1. Create a Single Looping Particle emitter with a spawn rate of 3.
    1.1 Properties → Enable Requires Persistent IDs.
    1.2 Emitter State → Life Cyle Mode: self, loop behavior: once, Loop duration: 2.
    1.3 Particle Spawn → Add Velocity → Set Velocity 50,0,0.
    1.4 Particle Update → Generate Death Event.
  2. Duplicate the emitter.
    2.1 Emitter State → Loop Behavior: Infinite
    2.2 Delete Spawn Rate, Add Velocity and Generate Death Event.
    2.3 Add an Event Handler → Set Source to first emitter Death Event.
    2.3.1 Execution Mode → Set Execution Mode to Spawned Particles.
    2.3.2 Spawn number → Set to 1.
    2.4 Add Receive Location Event.
    2.5 Particle Update → Add Gravity Force.

Minus the colors, it should look like this

DeathEvent-ezgif.com-video-to-gif-converter

For some reason, when the last particle from the first emitter dies, the death event always spawns the double amount of particles sets in the Event Handler Properties-> Spawn Number.

Am I doing something wrong or is it an issue coming from Niagara ?

Hi. I reckon this is a bug. You could get that last particle ID and use a kill particle module to deal with it.