I'm trying to figure out how water runoff from the roof could get behind the gutter. The area is on a shed dormer with a drip edge vent. I see water collecting at the bottom of the gutter where it sits against the fascia. It then runs down the face of the board to the bottom and drips off. The area is at the peak of the gutter. I removed the screws holding the gutter on in this area thinking water may be running off the roof onto the support bracket and down the screw, but that did not seem to fix it. I tried pulling up on the drip edge and could not see water running down behind it. Thoughts?