Hi! I found the reason for the issue UE-84238. Is there intention to fix it soon or will it be on the backlog as the cascade particle system will be overtaken by Niagra in the future?
The reason for the bug is that in ParticleGpuSimulation.cpp in Init()-function is a line
RandomStream.Initialize(Component->RandomStream.FRand());.
RandomStream is initialized using component’s RandomStream FRand which returns float in range 0…1. Initialize of the random stream just sets the seed to the parameter value which is int32. Because the float is in range of 0…1, it gets trucated when it is converted into int32 and the seed is most likely to be 0 or REAALY rarely 1. For example, multiplying FRand return value by int32 max value (2,147,483,647) would fix the issue.