I’ve created a beam particle, but it always loops, doesn’t matter of beam settings.
Some of settings:
emitter loop to 1,
emitter duration range to 0.1 - 0.5
lifetime range to 0.1 - 0.5
It loops in editor (simulate loop unchecked) and after spawn as well.
I’ve tried changing like everything, but without result.
Looping beam is made by design or there is a simple way to make it play once?
I am experiencing this problem as well in 4.20. It appears Always on check box is just broken and Beams are always on no matter what.
Are you using Cascade or Niagara?
They fixed this bug in 4.21 UE-62477
We merged it into 4.20 in our project and it works correctly now.
As  mentioned, [it’s fixed in 4.21 version]