The program displays garbled text for special Turkish characters

As the screenshot below shows, HTMLHELP displays garbled text for Turkish special characters (the program's text, not the help which is not (yet) in Turkish). This was tested under FreeDOS 1.3 fully updated with FDNPKG update.

This looks like a charset issue, so I checked https://github.com/shidel/fd-nls/blob/master/htmlhelp/nls/HTMLHELP.TR but it's correctly encoded in IBM CP857. Maybe there was a charset mismatch when the file got imported from https://freedoslocal.sourceforge.net/ or it wasn't compiled recently?