The rest of the pie pastry was still in the fridge, so I decided on a repeat, but with a real cooking apple--Granny Smiths. And the result is something like an apple explosion--the pastry top is recognizable, but below that is a spread-out mess of apple mush. Has the Granny Smith ceased to be a cooking apple while I wasn't paying attention? Did some unknown variation in water content make these particular apples steam and go boom? I have no idea.
I will scrape up one with a spatula for my dessert tonight, but the other may be discarded as unable to be stored for future use.