Particle system randomly jiggling, can't find solution

Hello.
I set up a rocket engine and tried to simulate underexpanded (aka in space) rocket exhaust plume, using blender particle system and point density feature.
In the viewport everything looks good, but after rendering everything jumps like hell. Can you please help me with this?

A video presenting the issue: https://youtu.be/asReUicjBB0


And a blend file: https://www.dropbox.com/s/5ooooi2b0xrt0c3/test1.blend?dl=0

Thank you for help.

Ok, Solved. Turns out I only needed to increase the resolution of point density node.