V 6.5.2: Rename Folder does not work anoymore

I've been using WinSCP for many years. For a few days now, I haven't been able to rename folders using the GUI. Files still work. If I rename the folder directly via the command line using the mv command, it works. The strange thing is that I can then rename this folder using the GUI as well. The log file is attached. Renaming starts at line 400.