Back to the snake in question:
The distribution of black pigment is very interesting to me. Especially how it is divided so cleanly. What it reminds me of is some chimaeric leucistic axolotls that have one sided pigment migration similar to your snake. They end up looking white with black speckles to one side of their body. The pigment migrates off the neural crest during development in the egg. It looks like for some reason it migrated more heavily to one side with your snake. It could be that he is a chimaera (generally caused by an egg being fertilized by more than one sperm, or by humans splicing notochords together in a lab) or that something random during develpment interrupted that pigment migration. And who knows, it may be that whatever interrupted the pigement migration is genetic. If he thrives then time will tell either way. I hatched out a chicken once that was a chimaera. He/she/it was a fertile hermaphrodite, and had similar pigment migration to your snake. It had one orange eye, one black eye, and the side of the body with the orange eye had much less melanin than the black eye side with a strong line of division down the back. It will be very interesting to see this snake grow up regardless. Best of luck!