[Flex Fluid] Material always showing as Invisible/Transparent

This is what i see when applying a basic material


This is the build i used: https://github.com/NvPhysX/UnrealEngine/tree/FleX

Nobody experienced this?

I’ve got the same problem, but only if I try to build an own particle system. It looks really nice in the demo level. I figured out, that the Flex Fluid Surface is the problem. If I remove it from the particle system at least the particles are visible.