Sprites in a particle system flicker/shake when use local space is combined with small velocity values and velocity aligned sprites.
Reported and tested in versions 4.25.3(CL 13942748), 4.24.3(CL 11590370), and 4.23.1(CL 9631420). In version 4.25.3 particles appear to be stable on X and Y axis, however will flicker when transform is changed to higher values on Z axis.
Result: Particle sprite will start jittering and shaking.
Expected: Smooth movement, exactly like it behaves at the origin.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-98086 in the post.