STEPS TO REPRODUCE
1. Dual monitor setup with primary screen on display port and the secondary one on HDMI
2. Login with Xorg

OBSERVED RESULT
Primary screen: Wallpaper is completely black, task manager bar and mouse are showing correctly.
Right click with the mouse doesn't work and notifications appear in the middle-left side of the screen.
Secondary screen: Wallpaper shows correctly and all behave as normal.

After the login, if I disconnect the Display port and then reconnect it after a couple of seconds the wallpaper reappear in the primary screen and all works as intended until the next restart.
On restart/logoff the issue repeats.

EXPECTED RESULT
Wallpaper shows correctly in the primary screen with no issues.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: ArchLinux with KDE 5.23.5
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Both screens have set the same kde default wallpaper so permission issues are not the cause.