This fall, water was discovered between the telescoping cover and inner cover. The dawn temperature of 45 °F, thin plywood construction of the telescoping cover and warm moist hive air is a recipe for condensation. In the morning, I also discovered condensation on the landing board near the reduce hive entrance.
Using 2 pieces of Styrofoam Block 18"x12"x1" from Micheals, a 1" slab of Styrofoam is fitted to the inside of the telescoping cover. The small bee escape notch on the top side of the brushy mountain inner cover permits some warm moist air to leak from the hive. See the photo--Now, the warm moist air leaking from the hive is seen appropriately condensing on the outside of the telescoping cover. Problem solved, I no longer find water between the telescoping cover and inner cover.