I saw the spinning circles as the thumbnails loaded as well but once the screen filled with thumbnails they started flashing and many of the thumbnails were white and flashing (which was most annoying). I am using build 103369.
If you have a search category that does not fill the screen then the display is ok.
EDIT: I have just been able to load the More Content screen onto TRS19 running on a different computer and it does not show the same problem so it could be an issue with screen resolution.