Some Songs will play too often (up to 5 times repeting) in 'Focus!'

Sorry for bad english!
If I choose a song and say ‘play similar’ roon select about 71 CDs and start playing.
One by one in shuffle mode.
BUT!!! Suddenly some songs play 3 times, some 5 times. How can I switch this off???
How can I delete oll the double-songs??? I think I have a lot!!

Thank You and all the best for 2017!!

Fenja S