If you have set a custom wallpaper on each virtual desktop then that will happen.
Windows 11 is prerelease software and so isn't currently officially supported and that new feature of Windows is something the current version of DeskScapes 11 is not aware of.
DeskScapes 10 will not receive updates for Windows 11, but DeskScapes 11 (in beta currently) will do. I don't know which version of DeskScapes you are using.