It's possible it's a chimera. A chimera is a mammal that started out as two seperate fertilized eggs and fused into one very soon after. The animal ends up being a fusion of two seperate sets of DNA. It is quite rare and not inherited as they pass on genes from one or the other but not both. This is different from a mosaic which is the result of a genetic mutation in one cell early in develop being replicated in only parts of the animal.
If one line of the rabbit was cchl cchl and the other was cchl c and they combined, I could see something similar to this being the result. No way to prove it other than genetic testing of both seperate color areas to see if they are different.