I'm not sure that the CD you added has had anything to do with this. There is a known issue where playlists are dulpicated on iTunes match. It hasn't happened to me, but I believe that it's caused by creating playlists on an iOS device when it is not connected to the internet.
Have you created any playlists on an iOS device since signing up for match? If so then I would recommend that you do a search on this forum for "duplicate playlists" or something like that. There is some useful advice within those threads.
I did create a new playlist saturday on my iPhone, I went on holiday so it didn't had a chance to sync with my Mac.
Yesterday I came back from holiday and I have worked on it for a whole day, so shouldn't the playlist have come the minute my iTunes had a chance to sync with my iPhone? But they didn't...
They came when I added the album, so that's why I think it's connected with that album.
But if it is actually from the playlist I created on my iPhone, how do I solve this?