Why can Particles appear/disappear?

Question

3ds Max

I make astronomical video, space, everything. Distant stars made as a cloud of particles (Particle Flow). There are 5 settings in total, Birth(-200start, 000stop), Shape(sphere 20sides), Display(Ticks), Position object, Material(glowing white).
Everything turns out as I wanted, except for one annoying detail. The stars "blink" when they shouldn't. In the max itself, you can see that the particles are motionless and do not appear / disappear, but there is still a blinking when rendering. What could be causing this and how to fix it?
Three frames (If you look closely at the edges, you can see that the stars appear / disappear)
edit1: there are 10000 stars [particles] in total, of course all shadows / reflections, etc. are disabled for them.
edit2: when the number of particles is reduced to 1000, the problem repeats.