What WACUP version & build type? Also where specifically in the UI are you triggering a playlist rename to occur? As seeing such characters would imply a bad string conversion happening (with the OS trying to represent string data with a wrong assumption) but I'm not seeing such a problem from a quick re-test with the current build when renaming in the places I can think off (i.e. the media library navigation tree node & within the library playlists root view).