He's a YB with a little mild incubation effect.
Ball pythons can take on an appearance outside their genetics quite often. Even with proven morphs. I see so many imports every year it's interesting to see how many actually do. Most of which are incubated on their natural environment, which means its not just a temperature spike that can cause it. Seems as though almost any developmental issue can arise during incubation.

Here is a couple YBs with mild incubation and extreme incubation effect. Hope this helps. My guess if you'll hatch out some nice YBs, but they probably won't look quite like pops.