Just try loading an expression map into the editor and saving it under a different name! You won’t be able to do it. The named expression map retains it’s original name every time.
The workaround solution is to use the Finder to rename your expression map file name to the desired name AND THEN call up the expression map into the MacOS text editor and change the name inside the xml file. What you see in Cubase in the list of expression maps pulled from what’s in the xml file itself and not the filename itself.
Clearly the “Save” command should be looking at the user entered name and updating the xml file before saving, but it’s not doing that.