People recognition stops incomplete

When the face detection runs and it identifies "new faces", it is designed to only show those new faces in the People View if there are at least 5 instances of that face in the library. So if in your library there are less than five photos containing a specific face, that "group" will not show up in the People View. However, once a face has been "named" then that restriction does not apply, i.e. you can have "named" faces with only one image, and that face will appear in the People View.

To get those unnamed faces to appear in the People View, select an image that contains the face that you want to name, then open the Keyword panel (by clicking on the "tag" icon bottom right of the screen). You will find that any identified face in that image (named or unnamed) will be listed in the panel above the Keywords section. Unnamed faces will have "Add name" alongside the face thumbail, and you can click in that field and type the name. If there are more than one unnamed fces in the image, open the image in the Detail view, then when you hover the cursor over one of the small unnamed thumbnails in the Keywords panel you will see a white rectangle appear on the main image over the corresponding face. That way you can more accurately match the thumbnails to the real image faces.