I loving it
Do u think that it worked ? What _melo
Which phone and android version do you have? Are you using a custom launcher or just stock?
You could try to set the wallpaper from the launcher and not from your gallery or any other app. Longpress on a blank spot in your screen, tap on change wallpaper and select the app and picture. See if that makes a difference. There're some phones that this process couldn't work.
This has been happening to me too, since I upgraded to lollipop. There's no rhyme or reason to it for me. I'll be doing something on my phone and when I go back to the home screen it will be the ugly stock wallpaper. I seriously hate lollipop. My phone is a total piece of crap now.