I still can reproduce this in v0.6.5, but I think it only occurs within folders that contain special characters. I write my notes in German, so there are some folders that have german umlauts in them (like ä, ö or ü).
I also tested this on folders that contain characters with accents (like é), and it happens there, too.
Additionally, when creating such folders, the folders immediately disappear once the name containing the special character was entered. So I guess it is some kind of encoding/unicode related bug.