If I ever get other ones...I have never observed the trio of conradti mating. One DOES look like it may be gravid, though....just have to wait and see!
Those eggs were laid very soon after I got them. As recent imports, the conradti were in average condition for WC, and took some time to fill out and become healthy. So perhaps it was only that the female's condition was not good enough to provide proper nutrition for the hatchling in the egg, so he hatched out too weak to make it.
They're healthy and active now, so that shouldn't be an issue with future clutches.