Your pie dough may be too dry. Add a few drops of water to the dough, not too much or your dough may become rubbery, and knead the dough a few times until it comes together. You can also skip the water and laminate your dough, this make your dough much stronger and will result in an extra flaky pie crust. For more on lamination check out my post on how to make Extra Flaky Sourdough Pie Crust.