When trying to click a directory with non-ASCII characters in the name in the places pane, in the file/directory picker in KDE4, it does not go to the directory. In the directory picker it seems like it goes to the directory above it, while in the file picker it doesn't do anything. The affects Firefox, which (at least on OpenSUSE) seems to use the KDE file picker when running KDE.
KDE 4 is unmaintained and has been for 3 years. Works for me in KDE Frameworks 5.45.