Im running into the same issue...
ive created a playlist for my wife's favorite games (Celia's Selection) made some cool art for the clear logo and added a cartoon of her as the device image. so far so good....
then i generated the 24x24 .png for the icon file. placed it in the \LaunchBox\Images\Platform Icons\Playlists\Celia's Selection.png i then realised the name of the playlist might be the reason the image wouldnt load... so ive renamed my playlist "Celia Selection" ... renamed my file "Celia_Selection.png" to match the standard.... still woudnt work. Im a paid premium user, I use 13.23. so as a last resort i decided to try again but renamed the playlist "Celia" made the icon Celia.png and it still wont load the icon.... it's such a little detail hehehe but it bugs me that it just wont work... i have the playlist set to show with platforms but even in the playslist view it wont load. please help
here's the culprit: