the window trim/flashing on the 45 degree angle. it appears that the joint looks like a miter cut connection. That is completely wrong and water will 100% enter that seam. how its supposed to be done is the "bottom-up" method. One square full size piece of trim on the bottom, no 45 degree cuts. Then the vertical pieces LAY OVER the bottom pieces so water runs down the vertical and over the lower horizontal trim. To make it look nice you cut the vertical bottom on a 45 degree angle so it APPEARS to be a miter joint but its really not.
the OVERLAPPING of trim pieces makes it impossible for water to enter. That miter joint right there is just pulling water in.
Trim/flashing is alway done "inside-out, bottom-up" to make gravity your friend..