During a Duels run, I encountered duplicate card buckets being offered - as Shaman, I was offered two copies of the “Elemental Assault” theme with identical cards (Marshspawn, Molten Blast and Serpentshrine Portal) after a match.
As far as I understand it, the intention is that you can be offered the same “theme”, but not the exact same three cards. Surely this can’t be intended, as it effectively means the player is only being offered two choices.
I have a screenshot of the above, but cannot post links.