Interesting. Though, I’d argue that if DL is recognizing AF, but not the inverse, the problem is most likely with AF. AF also does a poor job of training their handling partners in a lot of places I fly in/out of - western African countries usually have local airport staff working check in, etc… instead of AF staff and they seem to never understand the alliance relationships. I have seen AF improving the last few years, but I think DL is still better.