Hi so I’ve been testing around with card duplication during matches resulting in sceneraios such as 5 machop and glitchy energy as reported previously. I have tried to locate the problem and I think I have the answer.
It appears that whichever 2 cards you put at the bottom of the deck on underground expedition get duplicated and then replace 2 random cards out of the deck to maintain 60 total cards in the deck. as demonstrated here.
I put a Zorua and a rescue stretcher on the bottom of the deck as per the effect of underground expedition.
as can be seen 2 zorua and 2 rescue stretcher are at the bottom of the deck, these 2 cards have been duplicated (and placed at the bottom of the deck, the mew is there for my pokemon communication). This is not a coincidence as I only run 2 rescue stretcher and 3 are visible.
I have a feeling this would be a very simple fix however as I’m not a programmer I cannot really say anything with such certainty. I only say it is likely a simple fix as I reckon it would only take a quick change to the code for these cards so I ask you guys to please give this at least a brief look. It could potentially just be a case where the code demands 4 cards go to the bottom of the deck or the 2 cards are accidientally placed at the bottom of the deck twice.
Along with other examples (below), it appears giving cards in the deck a known location results in duplication.
Thanks
Hiker: [BR] Max Elixir (BKP 102). Against a hand control deck and ended
5 machop with UE and maybe Terraforming: [BR] Machop (EXP 117). Grass Energy (EXP 162). 5 machop on field