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Not sure why your crusts are gummy, but here's a couple of suggestions to experiment with.
--Reduce the amount of water you use to bind the crust together. The dough will be shorter and less moist.
--Let the dough rest before rolling.
--Roll a thinner crust.

Sprinkle sugar or brush bottom crust with lightly beaten egg before filling might help too.

Rest the dough. Shrinking and/or soggy crusts are often the result of dough that’s not given a conditioning period. Resting in the refrigerator for a minimum of 30 minutes or more before rolling it out is ideal.

Roll quickly and efficiently. Short on handling means long on flakes.

Rest it again. For an easily removable crust, lightly grease the pie pan. After the dough has been rolled and fitted into the pie pan, let it rest in the refrigerator while you prepare the filling.

To keep the fruit from saturating the crust, brush an egg white over the bottom and let it set for several minutes before adding the filling. Setting the pie on a baking sheet also helps prevent soggy bottoms.

I'm aware of most of these techniques already. I use half iced vodka half ice water to make my dough (Cook's Illustrated trick). The alcohol evaporates, yielding a shorter crust, and I only use enough liquid to barely hold the dough together.
I always rest my crusts in the fridge for at least an hour before I roll it out, and usually overnight.
I bake on a cookie sheet on the bottom rack at 425°F. for 30 min, then reduce heat to 350°F. for 20 min.
I do use approx. 3 tbsp. cornstarch to thicken my fruit pies, but I tend to overfill with fruit for a thick. deep-dish pie. I guess I could try to make them thinner.
I also use the egg wash trick with a blind-baked crust, like a custard pie or quiche, but never with a raw crust, so I will try that next time.
Thank you all for your suggestions.

@CJ McD-
You did help. Just wanted to rule out some of the other ideas as not being the obvious culprit.
I will certainly try your egg wash suggestion. I like the sprinkled sugar idea, too.
Thanks again.

It doesn't matter what kind of pie you're making, which pastry recipe you're following or whether or not you have a professional oven, these are the constants I learned 30 years ago from a couple of grandmothers who were truckstop cooks:

The dough doesn't have to be cold, but it must rest at least 10 minutes before rolling.

The bottom crust should be a little less than 1/4" thick, the top crust (if there is one) slightly thicker. Brush the top crust with egg wash before making the slits. The slits should form a ring between the edge and center of the pie (don't let them meet in the center)--they should be about 3/4" of an inch long and there should be six of them if you're serving six, eight if you're serving eight. When you make the slits, widen them a bit so that they won't close or get clogged during baking.

The filling shouldn't be at all watery before it goes into the crust, so don't give the fruit any time to macerate. Fit the bottom crust into the pie pan, roll out the top crust so that it's ready, then mix the fruit and sugar together. Fill right away.

Always place the pie on a cookie sheet on the bottom rack of the oven.

Bake double-crust fruit pies at 375 degrees until the filling is bubbling and the top crust is on the dark side of golden brown, usually 50 minutes to an hour, but sometimes longer. It doesn't matter if you use glass or metal--the temperature is 375 degrees.

I use the formulas for Julia Child's pate brisee sucre (my favorite for fruit pies), the America's Test Kitchen vodka recipe, Krusteaz Mix and recipes from Martha, Alton, Everyday Food, Better Homes and Gardens, A Taste of Home, the Chicago Tribune and Dorie Greenspan. No matter what the baking directions say, I follow what the two grandmas preached. Those women really knew their pies!

Cook your pies at 400 F. for at least the first 30 minutes. This will allow the crust to set up quickly. Depending on the filling, you can continue to cook at this temp, but would reduce to 350 for fillings that will cook quickly.

a darker pan will help with the browning and set up as well.

Be sure your dough is cold before it goes into the oven. Once the pie is assembled, place it in the freezer for 10 minutes to give the fat a fighting chance. Otherwise, it melts too quickly in the oven and can ruin the texture of the crust.

Allow pies to cool completely to allow starch and natural pectin to set up.

-Dawn
Eat dinner with your family tonight, I mean it.

Check your ratio of fruit/filling liquid to thickener, too. You may just have too much juice in there for the thickening agent to work, keeping the crust from being able to set up properly.

make sure to heat your cookie sheet while the oven is being pre-heated, then bake your pie on the lowest rack on the pre-heated sheet in the pre-heated oven.