io.elementary.settings crashes with "free(): invalid pointer" on startup

[oneLEAM]

What Happened?

Settings crashes immediately on startup with "free(): invalid pointer" and aborted (core dumped). The following critical error appears in logs before the crash:

GLib-GObject-CRITICAL: value "-1" of type 'gint' is invalid or out of range for property 'position' of type 'gint'

The crash happens during wallpaper preview generation in the Desktop plug.

Steps to Reproduce

1. Install elementary OS 8 (fresh install)
2. Open System Settings (io.elementary.settings)
3. Navigate to Desktop settings
4. Enable "Hide Dock when not being used"
5. Close and reopen System Settings — it crashes immediately on every subsequent launch

Expected Behavior

Expected: Settings opens normally

OS Version

8.x (Circe)

OS Architecture

amd64 (on most hardwares)

Session Type

Secure Session (Wayland, This is the default), Classic Session (X11)

Software Version

Latest release (I have run all updates)

Log Output

(io.elementary.settings:PID): GLib-GObject-CRITICAL **: value "-1" of type 'gint' is invalid or out of range for property 'position' of type 'gint'
free(): invalid pointer
Aborted (core dumped)

Hardware Info

CPU: AMD Ryzen 5 5600 (6-core, 12-thread)
GPU: AMD Radeon RX 580 (amdgpu driver, Mesa 25.2.8)
RAM: 16 GiB
Motherboard: ASUS PRIME B550M-K
Display: Dual monitor (1440x900 + 1920x1080), X11
Kernel: 6.17.0-19-generic x86_64
io.elementary.settings.desktop 8.2.1+r2288+pkg928~ubuntu8.1