Thanks for your feedback Dave - and for putting my mind at ease. It's great to know that I'm not the only one experiencing this particular issue.
I concur with your observation that the common feature is that the song title graphics for the tracks concerned fade out with a diagonal sweep. However, to compound matters it does not affect all DK tracks that have this diagonal sweep.
MTU – Your commitment to investigate the issue down track clearly reaffirms for me that my decision to purchase your product was the right one. Thanks for the Support.