The most common reason is a limited library of music scheduled in your Station in a 24-hour window. Rockbot recommends having at least 1,500-2,000 songs scheduled in a Station to avoid any type of repetition.
In addition, check to make sure your energy filter matches the tempo of music that is set in your scheduled station. If your energy filter is set to a higher or lower tempo than the music scheduled, you may have limited the content, therefore, you’ll hear more repetition. The energy filter feature tells our smart system to only play the type of music that matches the tempo that your energy filter is set to.