Single gamepad is controlling both P1 and P2 at the same time in Mame

[supersoundwave]

Hey all, first post!

I have 2 Xbox gamepads connected to Mame for 2 player games. I used each gamepad separately when selecting Input Assignments for Player 1 and Player 2 respectively.

But when entering a game, Player 1's gamepad is controlling both P1 and P2 simultaneously.

How do I fix this?

Thanks for any help :)