Visited a new build job site and couldn't believe what I found. The wall to the left of the window has OSB sheathing while the wall to the right of the window does not (see tar paper). Here is where it gets good. Below the window they did not use OSB but merely used whatever they had laying around. First you have an aluminum faced foam board, below that is a wood piece, then below that is MDF board. You can see the huge gaps between each of these dissimilar materials.

They will just throw some fiberglass batts and seal it off with drywall. On the outside they will just throw stucco over it and call it a day. How many leaks and rot issues will they have? What about the thermal bridging with those 5 pieces of lumber slammed together for the window area?