So sometimes when I move my Virtual Desktop with the pager, the desktop does not move and all the icons and wallpaper are still on the other work space. on the new work space all I see is black where my Desktop should be. It only happens on my main display. My second display remains unchanged. This happens on both my Laptop and Desktop running Plasma 5.4.1. It started after the upgrade to Plasma 5.4 which added a whole lot of stability to my system minus this one issue. My quick fix is to kill plasma and relaunch it whenever it happens.

Hi! If this is a regression/bug you should probably file a bug here https://bugs.kde.org/