When click on just Empty Log Files eventually you’ll get a Message stating Log Files have been deleted.
Looked in SongKong Log directory and there was over 100 meg’s worth of logs that weren’t removed. It appears it is only removing the .log.ick file and not removing anything else. Example songkong_debug0-1.log, songkong_debug0-2.log, songkong_user0-1.log, etc.
The .log.lck file is created when SongKong is in use and removed when it is not in use, Empty Log Files does not delete this. Are you using Nas/Docker version, if so makes me think that maybe you have configured /songkong location differently (or forgot to configure this time as optional) and you are actually looking at a previous location that you are not using.