Why is arcpy ChangePrivileges_management adding a second feature class to map?

Question

I am new to GIS and pretty new to python, so sorry if this is ugly code. I am creating a feature class in a postgres database if it does not already exist and the user wants it created.
That works fine, and adds a single layer to my table of contents in my current map. I added the line to change the privileges of the layer, and now I get a second polyline feature class added to the table of contents. Named a little different, and it does not stored in the database (the first, correct polyline does get stored). Where is this layer coming from, and how can I make it not show up?

   is_there = False
   matched_layer = False
   for fc in arcpy.ListFeatureClasses():
       regex = re.compile("skld_geodata\..+\.A%s" % sectional_name)
       if regex.match(fc):
           matched_layer = fc
           is_there = True

   if is_there is False:
       msg = 'No skld layer currently exists for this Arb.  Would you like to create one?'
       create_input = pythonaddins.MessageBox(msg, 'Missing Layer', 4)
       # create a new geodatabase entry with the correct name if it does not already exist
       if create_input == 'Yes':
           arcpy.CreateFeatureclass_management(shp_path, arb_name, 'POLYLINE')
           # change the privileges for everyone to work with
           arcpy.ChangePrivileges_management(shp_path + "\\" + arb_name, "editor", "GRANT", "GRANT")
   else:
       geo_layer = arcpy.mapping.Layer(matched_layer)
       arcpy.mapping.AddLayer(self.df, geo_layer, "TOP")

I can add images of the table of contents if that makes it easier to understand what I am asking.