Relative Folder Path in m3u incorrect?

I tried opening an m3u file with absolute paths in mp3tag, and then exported this playlist again.
The resulting m3u file now has relative paths, but unless I'm making a mistake, it looks like the path is wrong.

The playlist file is located here:
C:\Users\Gwen\AppData\Local\djDecks\settings\Gwen\playlists\mp3tag.m3u

The first file in the original playlist was:
c:\Music\Dance\Retro House\serious beats 25\cd3\track03.mp3

The first entry in the new playlist is:
..............\Music\Dance\Retro House\serious beats 25\cd3\track03.mp3

I've counted it several times, but the following path:
C:\Users\Gwen\AppData\Local\djDecks\settings\Gwen\playlists..............\Music\Dance\Retro House\serious beats 25\cd3\track03.mp3

resolves to
C:\Users\Music\Dance\Retro House\serious beats 25\cd3\track03.mp3

so it looks like there is one ..\ too little, unless there's something I misunderstood about relative paths in m3u files.

The strange thing is that winamp opens this new playlist correctly, but I'm not sure why.
Did I make a mistake here, or is this an mp3tag bug?