Simply this: controller 1 ghosts a 2nd button in it's mapping. I built these pads with instructions and a decoder map in hand so I could find lil problems. This problem however, just bugs me.
I press A, both A and X are pressed. b-y c-z triggers also have the same effect.
what bugs me more is that the second controller works fine. I swapped pads, tried 1controller drivers, both NTpad and psxpad do the same thing. I think the diode that branches to player 1 might be to blame.
BTW, they are digital pads
I had that problem with Joypads once,
It only did it on some programs (programs that were "compatible"),
I think it was a driver problem.