My two systems are affected: Arch Linux, plasma 5.12 beta neon dev unstable start Wayland session open system settings > display and monitor change scale setting to 2 and apply the new setting restart your computer and start Wayland session again display scale is 1 instead 2
Thanks for the bug-report! Could you please collect the debugging informatio as outlined on https://community.kde.org/Solid/Projects/ScreenManagement#Debugging_Information and attach to this bug? It'll help me to figure out where the problem is.
Created attachment 110209 [details] kscreen.log I just noticed that the screen resolution is also lost after restart. Should I open a new report about it?
Created attachment 110210 [details] screen configurations1
Created attachment 110211 [details] screen configurations2
Seems already fixed. Both display scaling and screen resolution settings are remembered on my Arch Linux running plasma 5.12.4. \o/