Rekordbox not exporting all data...

Will explain as simply as I can, hope someone can help this is driving me mad!

I have exported all my music onto my portable usb device with playlists etc etc.

Now when I am back in rekordbox making changes to tracks ie changing track colour, add comment or change rating, when I then export the changes to my USB device the changes are not transfering across. it dosent seem as though the original track is being overwritten.

However, If I was to add hot cues or cue points, these WOULD transfer across and overwrite the original track on USB device.

So why is the tagging I am doing in Rekordbox not updating the track on my USB device??

Any ideas very much appreciated.

Paul