Yeah it's on SNES. I haven't run any other system quite enough to say that is replicated anywhere else. I know the Saturn likes to duplicate the 7th card.
Yeah after running on both SNES and Saturn, this is definitely true. I NEVER got a duplicate on SNES. On the Saturn, I would get multiple duplicates a night. I also found that I was getting the exact same cards on resets of the Saturn way more often than the SNES with no intentional RNG manipulation.
I actually like having the categories - haven't submitted any yet myself but plan to start working on it. At least it adds some things to shoot for. I mentioned to my wife (before seeing this post) a few hours ago that it might actually prevent a number of resets; start an any% run, first few maps go south, convert it into another run.