I'm not sure if this is a bug but it occurred in both fceux,mesen and nestopia. I can't find anything on the wiki that would suggest this is normal operation but perhaps it is.
If player 3 HOLDS down+right, "B" and "start" are not recognized on the player 1 controller. I tested this in a couple of commercial 4 player games (Gauntlet II, Super Off Road for the NES).
Conversely if player 1 holds "B", if player 3 holds "right + down" it does nothing.
If player 3 HOLDS down+right, "B" and "start" are not recognized on the player 1 controller. I tested this in a couple of commercial 4 player games (Gauntlet II, Super Off Road for the NES).
Conversely if player 1 holds "B", if player 3 holds "right + down" it does nothing.