When I set my lockscreen and wallpaper, I set both the same, but now the lock screen wallpaper keeps defaulting back to a Samsung wallpaper and as much as I try and change it back, after an hour or so, it'll change itself back to the Samsung one. It's getting really annoying.
Is the wallpaper a photo from the Gallery or Samsung Wallpaper? Have you verified it is compatible with your Android version?
Have you tried wiping the cache partition on your device?
@userofnqxjeBqW Do you use a launcher on your phone or have you had one installed recently?