The KA0UPPMR (book in 'P') MIABOS fare you looked at was set to expire on 30AUG, and AA didn't extend/file a replacement. AA now only offers YA0UPAMR (book on 'A') in that market.

I am not sure if it's by design or by mistake: all of AA's competitors still have the 3rd tier first class fare filed, but none of them flies that route nonstop. And legacies are known for extorting/taking advantage of fliers when they're not checked by more ethical competitors.