It can be easily reproduced.
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Create a new particle system
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Add the Ribbon Data Type
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Set Max Particle in Trail Count in the Ribbon module to 10000000 or more (on my computer, it is enough to lower the FPS to 1)
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Put it on an empty level
So, a new particle system have default emitter duration is set to 1 second, and default spawn rate to 20. This means that in one second will be spawn 20 particles and then the emitter will start again. Default particles lifetime is 1 second too. Thus in fact, we have no more than 20 particles at any one time.