Phase one. 15.0.3 to 15.1.1
Ok this is a highly customized site that has some very good flow and design. The e-communities side of the website is experiencing a melt down in style and formatting.
In particular the Login and Default e-Communities pages throw js errors while navigating through the site. These were fixed and used to identify the session state failure.
Trapping the JS error helped Identify a rendering loop that causes bizare behaviour in the rendering sequence.