I have some new trucks. the left pedal have an electrical switch, then there is not a brake pump asociated to this pedal.
when you press it, the trucks does not have traction, and slowly will stop. But if you are in a tilt, the truck will go down still if you are pressing the left pedal.

If you need to stay quiet the truck completely, you have to press the brake button that is in the levers zone (red button)

I hope was useful,

The Brakes should turn on when you press the Brake/Inch pedal.
You might have to replace the dump valve. Part# CPHY0003-00 in stock. Run pressure test to confirm

if this is a combi lift 4 way i believe that the newest ones still drive with the pedal right down , we had one contacted combilift they said the driver manual states that the stop button brake sould be applied before revving in gear

No for all vehicle is same when you pres inching pedal down you turn off gear box and if your machine still roll you have problem somewhere in sistem it is like on car with manual gearbox.I think that you understand me.