It happens with snakes. Its seemingly random, but so called "slugs" (unfertilized eggs) are relatively common. Some might also seem fertilized but go bad while incubating due to it not being viable in the end.
There is a reason why most snakes normally breed with multiple males so the eggs have a higher chance of being fertilized.
It's no different from the chicken eggs that you eat now. Breeders actually like to give those Slugs to snakes or other animals that eat eggs, since they do have a nice nutritional value.

WHAT ABOUT THE OTHER BABIESSS!!!!!!!????