Under General > Non-Sequential tab, you will be able to set the maximum ray intersections per ray. If a ray encounters a surface of an object it counts as 1 intersection and if you are tracing "split rays" and also have "use polarization" then you could reach the maximum you set under this tab.Increasing this number would help to solve but you dont want to set it too high as it will use a lot of memory and trace the ray section that only carry small negligible amount of energy. Alternatively, you can also change the minimum energy threshold for non-sequential ray tracing so that the ray tracing will terminate at this energy threshold. Again watch out the minimum energy detectable. Hope this helps!!
