I see that this question remained as it is without a reply for a year!! I have the same problem even with artist or track mix. after like 20 songs it starts to repeat the same songs. very annoying! 

I understand that it is not perfect and doesn’t work as expected sometimes, and I have reported this to our Flow team already.
Since then they have considerably reduced the number of users that had the same track in the same day. They are also working and testing to reduce repetition during the month.
Apologies for the inconvenience and we appreciate your patience while this issue is finally fixed.
Thanks :)

I’m on my first day of the free trial. My very first ever experience using Deezer revealed this repeated track issue. I clicked on an artist mix button and heard the 2nd and 3rd track were back to back repeat and the 6th song was a repeat of the first. This isn’t looking too good so far.