Roger,
What kind of calcium/D3 supplement do you use? Do you dust every insect? I'm assuming the babies are indoors.

We have seen the same thing, and always attributed it to calcium/D3 defficiency. We never found out for sure what caused it, but as I recall, we switched supplements, and subsequent clutches seemed to do fine. We switched to Miner-all, but are now trying the Repashy brand supplements.
Collared lizards do seem to have a prety high demand for D3.