Instant mix playing from wrong directory

[grumpy bear]

I have a bit of a pondering issue.  I use the instant mix feature when playing music.  Which usually works great, however there has be a few occasions where it plays music from a different folder.  Nothing like listening to Alice Cooper song and then a Telly Tubs kids song.  

Media is sorted by Music, Christmas Music and Kids Music
Folder structure is Music/Christmas Music
                          Music/Kids Music
                          Music/Music

I am playing the instant mix from the Music/Music directory but it will also play from the Christmas directory and the Kids directory.

Any ideas of insight as to I can remedy this?

Thanks for any help