While there can be installation issues that can be the cause of water intrusion, proper shop drawings can allow reviewers to note concerns such as the lack of integration of gutter membranes (there are still those who do not utilize face sealed joints or cannot use them if the joint width exceeds that of face sealed assemblies).
Until as an industry we all recognize that and specify project specific shop drawings - firms like mine will be utilized to remediate water intrusion that is related to exterior expansion assemblies. Exterior expansion assemblies are part of the exterior building envelope.
