good day,
I too am having this issue, when I open my reg key (Computer\HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\R23.1\ACAD-3001:409) there is NO "Scale List"
also, this key doesn't exist in any 2020 product. AutoCAD 2020 and Civil 3D 2020 is the only version I currently have installed.
steps I used:
1: right-clicked on ACAD-3001:409 then NEW then KEY, rename "New Key #1" to "Scale List"
2: downloaded your zip "DefaultScaleList_2020_AC_EN.zip" file and imported that to my new KEY
3. save / exit reboot machine and launch AutoCAD.
this key remains until I open "Default Scale List..." and edit a valve then its deleted and I am back to where I started.
it doesn't matter if it's Metric or Imperial or AutoCAD / Civil 3D ALL edits are gone and the values are back to the original.
side note, I can open _SCALELISTEDIT and my list from the template are still there, but if I RESET they are then messed up.
thank you