This is might just be normal operation if all units react the same.

These units do not have a conventional mechanical service brake system.

I usually get this call when a new operator that has never driven a combilift before doesnt understand how the truck operates and assumes its like a normal counterbalance truck with a mechanical service brake.

The inching pedal dumps the drive pumps pilot pressure for the swash plate to tank returning the swash plate to its neutral position.

The truck slows down due to the 3 hydraulic drive unit wheel motors natural resistance.

The inching pedal also has a brake switch located beneath it. The operation of the switch is to apply the parking brake after a time delay which is usually set around 2 seconds.

The unit will have an increased stopping distance depending on the weight of the load its carrying, the speed of the unit before the inching pedal is depressed as well as the grade at which it is trying to stop on.

I highly suggest that the operator reads all operating guidlines in the operators manual.

Only thing that may cause an issue is if the inching pedal is out of adjustment and is not dumping full pilot pressure to tank in the fully applied/down position.

Easiest way to tell would be to unplug the switch beneath the pedal. Start the truck. Fully apply the inching pedal. Place the unit in drive and rev up the engine. If the unit starts to drive on flat ground, the inching pedal will need to be adjusted.