That looks like something truly special and not something I've seen before.
Bi-color petals are pretty common in some hybrids as you probably know, but I've never seen this "besseae flavum" background color with bi-color petals having the top halves with typical besseae coloration.
Also interesting are the clonal names of the parents, given this outcome.
I hope this is stable coloration (sounds like it is). It's a plant I would treasure for sure. Hope to see more hybrids like this.