I believe this large hole at the bottom of the awning mounting bracket is the problem. Any water directed down the inside of this channel by the support arm could leak through the hole & run down the back of the bracket. In fact, I'd say that discoloration at the bottom of the hole was caused by exactly that! If the holes for the mounting screws below are not properly sealed the water could make it's way into the wall.
Note how the U-shaped awning & intermediate support arms gently guide any water coming off the awning (or that simply fell there) right to the inside of the mounting bracket?
I've not noticed any water intrusion at the rear end of the awning, but I'm wondering if the adjustable intermediate arm there is allowing the water to drain through the slot?
This is the mounting bracket at the front end of the awning where I noticed the leak. I temporarily caulked around the hole & down along both sides of the bracket for good measure. That sloppy caulking on the mounting screws suggests more sealant is on the outside than the back side of that bracket. Given the fact my water leak inside is directly opposite & below this point suggests to me the water is entering the wall cavity right here!
