Created attachment 151441 [details]
Screen-shot of System Settings - Desktop Effects showing no vertical scrollbar.

SUMMARY
System Settings - Desktop Effects has no vertical scrollbar.

STEPS TO REPRODUCE
1. Launch System Settings
2. Navigate to Desktop Behaviour -> System Settings
3.

OBSERVED RESULT
Content exceeds window height and there is no vertical scrollbar. (Screen-shot attached).

EXPECTED RESULT
Vertical scrollbar present... :)

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20220817
KDE Plasma Version: 5.25.4
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5
Kernel Version: 5.19.1-1-default (64-bit)
Graphics Platform: X11
Processors: 2 × AMD Athlon(tm) 64 X2 Dual Core Processor 5600+
Memory: 3.8 GiB of RAM
Graphics:
  Device-1: NVIDIA G84 [GeForce 8600 GTS] vendor: Micro-Star MSI
    driver: nouveau v: kernel arch: Tesla bus-ID: 01:00.0
  Display: x11 server: X.Org v: 21.1.4 with: Xwayland v: 22.1.3 driver: X:
    loaded: nouveau unloaded: fbdev,modesetting,nv,vesa gpu: nouveau
    resolution: 1280x1024~60Hz
  OpenGL: renderer: NV84 v: 3.3 Mesa 22.1.4 direct render: Yes

ADDITIONAL INFORMATION
déjà vu :) -- I had this problem back in 2019 ( bug: 406182 ) In that instance it was caused by (an openSUSE packaging error?) missing "qqc2-desktop-style". This is not the case now though, as that package is installed:

paul@Orion-15:~$ zypper if qqc2-desktop-style
Loading repository data...
Reading installed packages...

Information for package qqc2-desktop-style:
-------------------------------------------
Repository     : openSUSE-Tumbleweed-Oss
Name           : qqc2-desktop-style
Version        : 5.97.0-1.1
Arch           : x86_64
Vendor         : openSUSE
Installed Size : 417.9 KiB
Installed      : Yes
Status         : up-to-date
Source package : qqc2-desktop-style-5.97.0-1.1.src
Upstream URL   : https://www.kde.org
Summary        : A Qt Quick Controls 2 Style for Desktop UIs
Description    : 
    A Qt Quick Controls 2 style engine that uses the desktop style
    to draw controls with QStyle.

paul@Orion-15:~$

Is there now a requires for a different (also missing?) package perhaps?

A default new user also exhibits the same issue of the missing scrollbar.