Ok, I've read a few complaints about this and can categorically say I have had duplicate cards on high low.
As sad as it sounds I used a single deck of cards to remove each card as it appeared, starting at the shuffle. About hand 9/10 I began getting duplicate cards with no indication of a reshuffle.
Could staff please confirm if it is a single deck? If it is not there needs to be a little work done to resolve this.
It was approximately 5 minutes prior to my post, but I don't have any problems in running another set of cards for you and noting down my entire set from shuffle to shuffle.
OK well I went ahead and played 4 more shuffle to shuffle and all worked out correctly, 32 cards turned each set and all different with indication of the shuffle made clearly.
I don't know if my browser type would effect anything but for the record I'm on an android tablet using Firefox.
Hmm, interesting, according to what I see in logs you had shuffles before the "duplicates" appeared. Perhaps it may b esomething with shuffle notification?
Let's do next: if you will play again, please try to record the exact shuffle and games time time (if there will be such issue and if it will be not hard for you of course) - we will check logs again. And there still be nothing to find the reason, I will set up some additional logging to catch such situations.