The expired Prazi Pro would not affect the fertility of the male so that wouldn't be the issue, at 90 MS that is not a bit high for fertilization for eggs. I use to get high hatch rates at 120 to 140. Is it a possibility that you may have 2 females that paired off? I had two females that paired one time and the exact thing happened that one would lay eggs and the other ate them. Other than than if you are positive the other one is a male then I would just take that one out and replace it with another confirmed male to see what happens.