Finally just finished my semester and have time to continue to work on my arcade cabinet.
I have updated to the latest version and I noticed that Start/Coin/Exit_Program button doesn't seem to work for both Player 1 and 2:
Note: I have tried assigning the Start/Coin/Exit_Program button to buttons that works but still didn't seem to fix it. (I am currently using a keyboard to insert coins at the moment as a workaround)