I am using Device owner mode on my Android device and am experiencing issues managing wallpapers on this device.
Administrator has set the wallpaper and all devices have the correct wallpaper applied.
However, when a device user randomly changes the wallpaper, the wallpaper changes.
Users also can't roll back wallpapers set by administrators.
Also, the SM does not recognize the changed wallpaper and the device does not use the wallpaper set by the admin until the admin changes the settings and sends the profile again.
There is a 'disallow set wallpaper' item in Google's Android MDM profile, which seems to prevent the above issue.
https://developer.android.com/reference/android/os/UserManager#DISALLOW_SET_WALLPAPER
However, SM does not seem to have this feature, and when I contacted TAC about this issue, I received a response that SM do not currently support this feature.
Other MDM vendors seem to support this feature fine... I don't know why SM doesn't support it.