I am having a similar issue. About 30 seconds - 1 minute after my wallpaper changes, the wallpaper will disappear and the background turns white. If I open the Windows control panel > Personalization, I can see that the wallpaper is set correctly:
I have tried disabling and enabling "Use transitions when changing wallpaper (Windows 7 and higher)" in the DisplayFusion Wallpaper Settings.
DisplayFusion version: Steam 7.3 Beta 2
Windows 7 Pro x64