I agree with Patty. The coffin bone may already have rotated. I knew a paso with hooves like that. His owner was absent and the boarders were feeding him in a group in the field. He was stealing grain and very obese. I spoke to the boarders but since the horses got "skinny" during the winter they were feeding them extra during the summer.
I asked them to separate the horses during feeding but they couldn't be bothered. They got reduced board for caring for the owner's horses, but it didn't sound like the owner cared either.
I removed myself from the situation. There was nothing I could do and nothing animal services could do as the horses are fed.
That paso also had the separation you are seeing along with dropped soles.