Render error - flickering lights/shadows on particles

[andrasszada]

Hey guys 
I have an issue with my render. There is some ugly flickering lights/shadows on my particles.
See the attached video clip.
I checked, it is not Vray issue. I placed a simple box in the scene with the same shader, and it had no issues.
So my guess it is tyflow.

I am using
tyflow v1.116
Vray 6 update 2.1
3dsMax 2025

Any suggestions or tips?

Thanks a lot!