This occurred to me during free version and premium version. However there is a solution to the problem in the free version. After every 3 advertisements the songs re-shuffle (like a pack of cards) and are rearranged. The fault in the shuffle version is that the rearrangement is algorithmly incorrect meaning that it reshuffles in the same order. One solution is to delete the common songs or to skip the common ones and listen to the occasional random one that you do my hear much. The system is time based and cut based meaning the amount of time spent on a song is utilised in the shuffling and reshuffling order and the amount of advertisements. The cycle will stop if the process is continued unless you are extremely unlucky and odds are hugely stacked against you in life. From an algorithm perspective it would not be possible to keep 'shuffling' and playing the same songs.