Mapped Domain suffixes "/blog" and causes recursive redirect

I attempted to configure the domain mapping plugin to configure a multisite blog, as it's own URL:
The Domain configuration page automatically suffixes "/blog" to the page -> Accessing this results in a redirect loop, hence I cannot utilize the the plugin. Other configuration values: Network redirect: OFF. Network DNS is not redirected (doesn't work when it is either).
What cuases the inclusion of the "/blog" suffix when it is not specified? How can I set parameters to adjust for this? Is there a way to turn off the automatic suffix?