The coronary band is prolapsed, meaning it is bulging out. With nothing to pull it down, the new hoof wants to grow out and over the old hoof. Normally, the new hoof growth pushes the existing hoof down as it grows because they're connected. It reminds me of an adult tooth pushing on a baby tooth. Sometimes one or the other is not lined up correctly, and the adult tooth will grow at a crooked angle if it doesn't have enough room to drop into place.
By late November, there should be sufficient new hoof to provide enough support for riding. The only concern will be whether the old hoof is strong enough to resist breaking away. If it's not, we can put on an eggbar shoe to support it while more hoof grows.
While I want to ride, I don't want to mess around with expensive shoes when I can get the same result by waiting a few weeks longer. I should know more in a couple of weeks, but it all looks good for now!