Although your feature class contains features of just one geometry type (in this example:
), the Style Editor for this layer provides ability to stylize all geometry types: points, lines, and polygons.
Another manifestation of this is the multi-feature icon that displays in Task Pane > Display Manager:
Geometry was originally set up to enable all spatial data types. Viewing the database's schema reveals this:
To stylize features, you'll likely have to use the long scroll bar to switch between geometry types.
You also might be able to change the definition of the spatial data type in the database itself to specify just
type of geometry.
Products: AutoCAD Civil 3D;AutoCAD Map 3D