It seems like a fairly minor issue but it seems like when updating the cosmic packages the wallpaper settings can lose track of the currently set wallpaper, leaving the preview in the settings blacked out
Upon further testing it looks as if the settings daemon may have crashed in the background, upon restarting it the settings started working correctly again
It seems like a fairly minor issue but it seems like when updating the cosmic packages the wallpaper settings can lose track of the currently set wallpaper, leaving the preview in the settings blacked out