I tried a small test project using S_NightSky effect.
It uses several expressions for its parameters, and with them I see a strange problems - some of the frames show several stars jumping for one frame and then returning back to their positions in the next frame.
(The number of such frames depends on unknown factors, but I see at least one such frame in the example).
Can someone check the attached project and test whether this situation is reproducible?
Stars-Test.aep (190.5 KB)