Wallpaper blur setting doesn't last after reboot on plasma

[Luca Osvaldo Mastromatteo]

Description: Ubuntu 18.10
Release: 18.10
plasma-desktop:
  Installato: 4:5.13.5-1ubuntu4
  Candidato: 4:5.13.5-1ubuntu4
  Tabella versione:
 *** 4:5.13.5-1ubuntu4 500
        500 http://it.archive.ubuntu.com/ubuntu cosmic/universe amd64 Packages
        100 /var/lib/dpkg/status
NVIDIA proprietary drivers 415

The wallpaper blurred background setting doesn't last until reboot, unless the wallpaper is set as a single one and not as a presentation in a folder. It reverts back to "Solid color"

The wallpaper blurred background setting should remain after rebooting the system, even if I set a folder background presentation.

Steps:
- Choose a folder where to get the backgrounds on plasma KDE, with a good looking blur effect on the angles instead of a solid color
- Reboot
- The wallpaper has solid color instead of a blur effect, the setting reverted to "solid color" instead of "blur background", see images. Only happens when a folder presentation is set, doesn't happen when a single image is choosen

Probably fixed upstream???

[Luca Osvaldo Mastromatteo (lukycrociato)]

Not present on Neon, the KDE distro, so it's an upstream bug which got fixed

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nicolas Kauffmann (n-kauffmann)]

After sleep and re-login there is a graphics-fail:
the central image is proper, the surrounding blur is damaged.

KDE
4.15.0-43-generic x86_64
Ubuntu 18.04.1 LTS
plasma

attached screenshot

[Luca Osvaldo Mastromatteo (lukycrociato)]

i don't think it's the same issue, the problem about that graphics corruption is due to the nvidia proprietary drivers, the issue I mentioned happens only on reboot and even if the GPU driver isn't the nvidia proprietary one

https://bugs.kde.org/show_bug.cgi?id=364766