I go to a local pet store, I've known the owner for over 16 years and he used to breed hedgies. So he was a wealth of good info when we got our hedgehog.
we have had the exact thing happen, with our Danko homobeige male & JASG Black velvet female. 4 litters all look like beige when born 50% ended up brown velvet.
we've had over ten since we've been breeding from different females, 2 of them more consistantly. I'll take twins or trips over quads anyday. Keeping all 4 is really hard.