This mutation can easily occur in those few pups that survived from inbreeding.
They cannot reproduce a lot or at all but they can still take part in every event or activity.
But let's stop for a moment and explain how it works:
Every time you get a geno, you have a lot of information and one that mentions that the kise is "healthy"; in imbreeding the puppies can have many problems and in this area it appears whether the kise is stillborn or has fertility problems.
A perfectly healthy Kiseilian, it has average breeding chances.
Their breeding chances are lower, they can have 1-2 pups, but there are good chances of empty nest.
They can't have pups, their breedings would always result in empty nests.
Inbred pups, even if bred from two healthy parents, might result as infertile or even sterile.
Whenua's blessing assure infertile kises to always have 2 pups but doesn't guarantee their survival.