Thank you everyone for all the input! I think my problem must have been the ambient temperature in my kitchen (it was definitely an unusually warm and awfully humid day, and I was working right under some pretty hot lights), and over mixing the flour and shortening. I didn't realize that it was only supposed to be cut in--I mixed it thoroughly, possibly even more than I usually do because I was distracted by everything I was working on. (I made eight pies last night, but only one of the batches of four had any problems.) I do know the problem is not old shortening because I'd bought it earlier that day, and I definitely followed the recipe.
But yeah, my kitchen was definitely warmer than usual, and all of my ingredients were the same temperature as my kitchen. In the future I'll be sure to keep things cold, and not over mix the flour and fat.
Thank you all so much! I looked all over online and I couldn't find any one else with problems like this, and I knew I just needed to ask people with experience and a deep understanding of pie crusts. :-)
Tonight I made chicken pot pies, and for the crusts I followed a recipe that I've used several times with happy results. However, tonight's pie crusts (though they looked quite pretty with golden edges) are almost inedible. The crusts are almost powdery, and when I squish the powder between my fingers it turns into a slimy substance that very much resembles pie crust dough. The crust tastes kind of like shortening, and it leaves a disgusting film on the room of my mouth that's difficult to remove. (The same film is left on my fingers when I squish the crust between my fingers, and it's only removed with soap.) When I put plastic wrap over the pies, bits of the the crust stuck to the plastic, leaving greasy, lumpy smears at any point of contact. Also, I know the problem is not that the crust is undercooked because the golden brown parts behave just like the lighter parts of the pie.
I used four cups of flour, two cups of Crisco shortening, salt, baking powder, lemon juice, an egg, and a little bit of water, everything as I normally do, so I'm at a loss as to what happened tonight. I didn't use any cold ingredients, which is only slightly different than what I normally do--usually at least the egg is cold.
My fiance *loves* this pie crust recipe so I doubt I'll ever use another, even though I know that there are many *technically* superior recipes out there. I just want to know what may have happened to make it awful so that I don't make any more crusts like these.