SUMMARY

Just upgraded KDE 5.26 stable to 5.26.90 using kde-unstable repo in pacman

Latte (both git from AUR and 10.9-1 from official repository) do not load any layout  (no icons/app launchers)

Latte dock presents a 'Latte Tasks' notification with the following message:

file:///usr/share/plasma/plasmoids/org.kde.latte.plasmoid/contents/ui/main.qml:599:9: Cannot assign to non-existent property "dragIconSize"

STEPS TO REPRODUCE
1. Archlinux update packages with repo kde-unstable 
2. reboot system
3. login and run latte-dock


OBSERVED RESULT
try different layout -- same message persist and no icons 

EXPECTED RESULT
getting back the application icons/launchers that appear fine on latte-dock running Plasma 5.26 stable

System info:
Operating System: Arch Linux 
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8
Kernel Version: 6.1.8-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 24 × AMD Ryzen 9 5900X 12-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 6800