Akishop PS360+ Problems with pressing select and another button

I have installed the ps360+ with no problems. All buttons/joystick movement work correctly.

However when I try to press both 'Select' + Any other button (e.g R2/RT) It does not register both buttons as being pressed at the same time.
This is not the case with say 'Start' + Any other button or with 'P1' + 'P2' etc

This is a major problem for DoA5 where the training mode shortcuts like restart position are accessed from 'Select' + 'R2'

Anyone come across this problem? I would appreciate any solutions.