It was working fine before converting to 4.17.1 from 4.16.3.
It works in the viewport as well as in the “packaged game” but all the instanced meshes disappear in the “stand alone game” I have checked the wireframe and they are not there. I have tried to reproduce this with a simple blueprint in an empty project and same issue. thx
A fix was made and will be available in 4.18.