So, what is the exact IIS setup?
2 sites, one points to the cms folder, and the other points to the mvc folder, both sites use same app pool,
What are the URLs?
these are only set up locally (host file just points to local ip.
What is set as the presentation URL?
Do the sites listen to each other?
not sure what this means
What authentication method is used? E.g. is the anonymous authentication enabled?
mvc has anonymous
admin has anonymous and forms
What application pool settings are the sites using?
both use the same app pool, ApplicationPoolIdenitity
Are you using SSL?
What is set as the application pool identity and disk permissions?
ApplicationPoolIdenitity, app pool is set to allow on all except special permissions
What hotfix are you using? There were several bugs also fixed in the page builder.
52 for mine dancing goat is 29, I'll upgrade dancing goat to 52 to see if it makes a difference. We have a live sites on a web farm that I'll move my stuff out to when it is ready so I didn't want to upgrade past 52 because of the hassle of upgrading the web farm version. (the live site we have also has the same issue, was just never a problem)
I just did a separate site setup in my IIS and it is working fine. There must be something not set correctly in your environment or in the MVC app code. When you configure the sample Dancing Goat to use two sites - e.g. just adjust the home folders for your current sites, does it work?
I'll check and get back to you