RetroArch only recognizing Port #0 from Mayflash Adapter

RetroArch is only recognizing the first port from Mayflash Wii U Pro Controller Adapter. I have two Pro Controllers connected but I am only able to use one. If I try to Input Player 2 Binds, the Index only shows “Mayflash Wii U Pro Controller Port #0” and "N/A (Port#4)