Controller Input Not Behaving as Expected on Android

I recently got a Retroid Pocket 2, a lightweight Android gaming device that has a built-in controller.

Minecraft does not seem to respond to the L2/R2 buttons, and the d-pad input is "sticky," meaning that if I press up on the d-pad, the input persists after the button is released until I press down (in which case, down is now the "stuck" input). All other buttons register fine in-game.

 

I can confirm that the affected buttons are working fine in other games and in the Android system menus. Please let me know if any additional information is required.