Solved - Actor thumbnails are not downloaded during scrapping

Hi, I manually download the various artworks (poster/fanart, etc., but no actor thumbnails as I don't want to keep duplicate actor thumbnails) for movie "2001: A Space Odyssey" (https://www.imdb.com/title/tt0062622/) and created a NFO file for it. The NFO file e has the following content:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<movie>

    <title>2001: A Space Odyssey</title>

    <originaltitle>2001: A Space Odyssey</originaltitle>

    <rating>8</rating>

    <votes>5367</votes>

    <top250>0</top250>

    <year>1968</year>

    <tagline>The ultimate trip</tagline>

    <runtime>149</runtime>

    <mpaa>U</mpaa>

    <playcount>0</playcount>

    <id>tt0062622</id>

    <tmdbid>62</tmdbid>

    <set>

        <name>The Space Odyssey Series</name>

        <overview/>

    </set>

    <sorttitle></sorttitle>

    <trailer>plugin://plugin.video.youtube/play/?video_id=QQpJgzBndlw</trailer>

    <watched>false</watched>

    <credits>Stanley Kubrick</credits>

    <credits>Arthur C. Clarke</credits>

    <director>Stanley Kubrick</director>

    <studio>Stanley Kubrick Productions</studio>

    <studio>Metro-Goldwyn-Mayer</studio>

    <genre>Science Fiction</genre>

    <genre>Mystery</genre>

    <genre>Adventure</genre>

    <country>United Kingdom</country>

    <country>United States of America</country>

</movie>

All artworks worked fine except the actor thumbnails. I tried both TMDB scrapper and UMS scrapper, but none of them would scrap actors information (and the actor thumbnails) for the movie. If I added the actors element to the NFO file, like the following, the actor name appears, but no thumbnails for it.

    <actor>

        <name>Keir Dullea</name>

        <role>Dr. David Bowman</role>

    </actor>

I thought Kodi will use information in the NFO file, and for any information not exist in the NFO file, it will download from internet, but seems this is not the case. How can I ask Kodi to scrap the actor information?

BTW, I had "Download Actor Thumbnails" option enabled in Kodi settings. From the progress bar at the top right corner during the scrapper, it seems Kodi never queried internet to get information for the movie. The whole scrapping process was too fast.