I don't know if this fits better here or in my other thread: I do not see this issue anymore as a matter of the colons. My suspect is that on APFS volumes you can't get the name of the start volume the same way like before.
This affects functions like info("volumes") and homepath(). I have made a test with the openfiledialog statement. This is the result for the folder variable in my test.
See what happens when I use
Hazel is not the name of my start disk; it is the name of another hidden (not mounted) volume, presumably belonging to a 3rd party pref pane "Hazel".
So it is no wonder that the HFS path is pointing in a wrong direction now.
Paths are working perfectly when you use the UNIX path syntax (with slashes like in the 1st screenshot and without disk name).