SUMMARY

After upgrading from Plasma 6.4.5 to 6.5.0, the mouse cursor appears as a wide streak of garbled pixels, rendering Wayland sessions almost unusable.

STEPS TO REPRODUCE
1. Be on Arch Linux, having the same hardware that I do
2. Upgrade the system
3. Initiate a Plasma session on Wayland

OBSERVED RESULT

The attached image shows the cursor to the left of the Virtual Desktops widget.

EXPECTED RESULT

That the mouse cursor is rendered correctly and that I am not required to initiate an X11 session or downgrade Plasma.

SOFTWARE/OS VERSIONS

Operating System: Arch Linux
KDE Plasma Version: 6.5.0
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.5-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 4 × AMD A10 PRO-7800B R7, 12 Compute Cores 4C+8G
Memory: 16 GiB of RAM (14.6 GiB usable)
Graphics Processor: AMD Radeon R7 Graphics

ADDITIONAL INFORMATION

This is a fairly old processor with an integrated GPU that supports the radeon DRM/modesetting driver. Despite its age, I have experienced no issues with it until now.

I believe the problem is attributable to kwin_wayland because my SDDM greeter is also affected in the case that I have the following sddm.conf option in effect.

[Wayland]
CompositorCommand=kwin_wayland --drm --no-lockscreen --no-global-shortcuts --locale1