I've submitted a bug report in-game, and I'm not sure how really relevant this will be with the reward changes in the upcoming patch, but I encountered a curious bug today. After defeating two PvP opponents I noticed that the Dueling Tributes (Marunji's quest) was showing that I could defeat a THIRD opponent or return to Marunji for a BRONZE reward. I thought this might simply be a visual bug, so I traveled to Marunji and spoke to him until I saw the quest rewards and, seeing that it was indeed a bronze-tiered reward, I exited without accepting.
I then decided to defeat a third opponent to see if that would fix the issue. After defeating said opponent, I saw in the quest log that I would still only be receiving a bronze reward. I decided to again give the game the benefit of the doubt and check if it were just a visual bug. Nope. Decided to eat the loss and accept the bronze-tiered reward.
This is mostly a PSA that if you experience this bug it may be best to just abandon the quest and start over if you care about the higher level rewards.