Adobe got back to me and there is in fact a setting for this that is off by default.As an Administrator navigate to Setup > System > Preferences and there is a checkbox for "Allow embedding or Workfront in an iframe". Worked perfect after that selection.

We are looking to include Workfront into our own marketing hub, meaning we want to embed Workfront via an iframe. Most of the interface works great but one issue we have is that it appears the "Calendar" functionality won't display across domains.    Is there a fix or workaround for this?