Carrier Wallpaper goes black 12 pro max

[Museo12]

Something very strange happened to my Iphone 12 pro max a while ago. My wallpaper disappeared and the background is now completely black. If you turn the phone off and on again, the wallpaper comes back. However, this is deceptive. If you go into an app and then exit it, it goes black again. Otherwise, everything works.

How can I solve it?

 

[JM]

Welcome to Macrumors!

Do you have any focuses set? (That would change wallpaper.)

Any shortcuts enabled?

 

[CP11]

Something very strange happened to my Iphone 12 pro max a while ago. My wallpaper disappeared and the background is now completely black. If you turn the phone off and on again, the wallpaper comes back. However, this is deceptive. If you go into an app and then exit it, it goes black again. Otherwise, everything works.

How can I solve it?

I also was having this issue with my iPhone 12 Pro Max. I came across this and so far it has worked.
Apparently, old photos used as wallpaper are triggering the black background. You can fix this, if you resend the old photo to your iPhone and save it in the Photos app. You can do it either via AirDrop from and older device, or from any other computer as mail attachment!