Display scale resets to 1.0 when screen locks

Hi community,

I'm using XFCE 4.18 and LightDM on EndeavourOS and facing a problem related to my HiDPI settings. I'm using a LG 5K screen with resolution 5120x2160. For things to be reasonably sized, I've set my display scale to 1.2 via Settings Manager -> Display -> General -> Scale.

This works perfectly until the screen gets locked automatically. As soon as I wake the system up, the scale is set 1.0 and I have to reset it to 1.2 almost every time. I can already see the wrong scale on the XFCE lockscreen login. Curiously, it doesn't happen when I lock the screen manually.

I tried to understand which exact values get set to 1.0 using this for loop:

for i in $(xfconf-query -c displays -l | grep Scale); do echo $i; xfconf-query -c displays -p $i; done

But it seems like none of the values are changing. When I go to Settings Manager, the scale is at 1x instead of 1.2x though.

I'd appreciate any ideas and thoughts! Sorry if this is the wrong repo for this problem. I'll gladly move it and provide any further info and conduct debug steps.

Before:

/2141747623de0b2ae63e285209d287132ec02d45/DP-0/Scale/X
1.200000
/2141747623de0b2ae63e285209d287132ec02d45/DP-0/Scale/Y
1.200000
/Default/DISPLAY/Scale/X
1.200000
/Default/DISPLAY/Scale/Y
1.200000
/Default/DP-0/Scale/X
1.200000
/Default/DP-0/Scale/Y
1.200000
/Default/DP-2/Scale/X
1.200000
/Default/DP-2/Scale/Y
1.200000
/Default/DP-4/Scale/X
1.200000
/Default/DP-4/Scale/Y
1.200000
/Default/HDMI-0/Scale/X
1.500000
/Default/HDMI-0/Scale/Y
1.500000
/Fallback/DP-0/Scale/X
1.200000
/Fallback/DP-0/Scale/Y
1.200000
/Fallback/DP-2/Scale/X
1.200000
/Fallback/DP-2/Scale/Y
1.200000
/Fallback/DP-4/Scale/X
1.200000
/Fallback/DP-4/Scale/Y
1.200000
/Fallback/HDMI-0/Scale/X
1.300000
/Fallback/HDMI-0/Scale/Y
1.300000

After automatic lockscreen:

/2141747623de0b2ae63e285209d287132ec02d45/DP-0/Scale/X
1.200000
/2141747623de0b2ae63e285209d287132ec02d45/DP-0/Scale/Y
1.200000
/Default/DISPLAY/Scale/X
1.200000
/Default/DISPLAY/Scale/Y
1.200000
/Default/DP-0/Scale/X
1.200000
/Default/DP-0/Scale/Y
1.200000
/Default/DP-2/Scale/X
1.200000
/Default/DP-2/Scale/Y
1.200000
/Default/DP-4/Scale/X
1.200000
/Default/DP-4/Scale/Y
1.200000
/Default/HDMI-0/Scale/X
1.500000
/Default/HDMI-0/Scale/Y
1.500000
/Fallback/DP-0/Scale/X
1.200000
/Fallback/DP-0/Scale/Y
1.200000
/Fallback/DP-2/Scale/X
1.200000
/Fallback/DP-2/Scale/Y
1.200000
/Fallback/DP-4/Scale/X
1.200000
/Fallback/DP-4/Scale/Y
1.200000
/Fallback/HDMI-0/Scale/X
1.300000
/Fallback/HDMI-0/Scale/Y
1.300000

Kind wishes, Valentin