Looking at your mailing, I see you are using a template called Summer 2015 Internal that was creating using the Save as Template Feature. Looking further, I see the Summer 2015 Internal template is based on our Bay Window template.
If I switch templates from Summer 2015 Internal to Bay Window, the issue with extra content appearing goes away. It looks like the issue is coming from the Summer 2015 Internal template.
I suggest switching to the Bay Window template (or create a new version of the Summer 2015 Internal template). You're also welcome to use the copy I made for testing (the one labeled Test Copy) if you'd like.