When creating a detailed view sometimes the show boundary feature does not work correctly. It sometimes displays the boundary around the entire spline defined boundary instead of just the edges of the model. I submitted a case to PTC but was informed that this is a limitation in the software and that I would best be served to post here in hope that PTC will address this in a future release.
The green lines indicate where the boundary should be displayed.
The red line indicates where there should be no boundary lines.