It is happening in this game (it is a private game) - Bone Sword Development - Roblox
It seems to be in sync with the gears in the background. Wild theory here, but do you have by any chance a script that loops through instances and if it’s a ParticleEmitter, calls Emit on them? If it’s game tied it surely has to be something specific you’re doing.
As being said above^
Can you search :Emit( and check if any script causes this thing?
The behavior looks really weird because, well, rate property determines how much particle will frequency emit per second, but here, we see that particle emits 3 particles at once plus desynchronized.
This was the culprit. Some old code that shouldn’t be there became active again, thanks.