I have a Niagara system that spawns mannequin static meshes moving on the x axis. In the video attached, if the origin of the Niagara system is within the screen, the Static meshes are visible. If I move the camera away from the origin of the Niagara system, all static meshes disappear. …

It’s probably culled because the visibility bounds are too small. Increase the bounds on your emitter or system to fix this.