I need some help/advice on what the "Faces with Zero map " means when I do a polygon cleanup. Quite a few of the faces are highlighted with this error and I have never come across it b4 . look at this pic https://www.stonks.com/help1.jpg

If I do a cleanup, those faces that are highlighted get deleted, and teh Maya help file doesnt give any explanation or indication how to fix it. Im pretty sure those faces were made by extruding other faces ?

Help