Which tag did you change?
I’ve seen some confusion in the past with the *.m3u files. In my case I saw duplicate versions of the same song, as the system was looking at the .m3u files as well as indexing the song itself. So it could be that you are looking at just the .m3u files, instead of the database. This seems a bit odd though. Anyway, you could edit the m3u file as a test.
What is your setup? windows/unix, ogg/flac/mp3, etc….. How many songs?