How can I get more Random?

In using Random Mix by Album or Artist I almost always wind up having numerous instances of the same Album/Artist or the same Artist lined up to play. Is there something I’ve done wrong, or is there anything I can do to overcome this?

I’ve checked the spelling and tags and there is nothing obvious that would distinguish these items as being different, but rather they are identical where they should be.

Stats: Win 8.1, LMS 7.8.1-1408670219, 1113 tracks, 504 albums, 257 artists. Scan time is fine, with no issues.

Thanks for any advice…….