So someone correct me if I'm wrong, but this makes sense. The bumblebee is a Pastel Spider, two genes which reside on different alleles. The Gargoyle is a Cinny Het Red, which are on the same allele. The Gargoyle parent is only able to pass on one gene from each allele, so it will either give the Cinny or the Het Red to the offspring, but not both. This is also why none of the offspring would be normal, since all offspring would either get a Cinny or Het Red gene.