I have a particle system where the particles have randomized lifetimes, changing colors throughout their lifetimes, and different patterns of changing colors depending on lifetime. The process works fine when working only with parent particles, but as soon as I try to enable children..... nothing happens. The children refuse to render. Well, they act more like their material is a holdout node. After poking around a bit I figured out it was related to the particle info node somehow. When manually entering values instead of using the particle info node, the node setup works as necessary... without the random values. Anyone know how to get this to work properly, with child particles reading from the lifetime imput?
This is a known limitation.
I don't see any mention of it on the todo list, but blender's particle system is scheduled for a complete rewrite for 2.8, perhaps it will be fixed then.