Homemade canned peach pie filling is great for cheesecake toppings, coffee cakes, tarts, muffins, cobblers, crumbles, and homemade pies. Besides, you can make big batches of canned peach pie filling to store for winter.
There are two possible reasons why your peach pie is runny whenever that happens. The first reason is that your pie may not have the right enough time to cool down.
The second reason is that your pie might not have gotten hot enough inside the oven or did not have enough time to boil properly. In essence, pie-filling bubbles activate their natural gelatin in the peach and the thickeners you have added to your pie.