I will not be of much help. But I have a similar system.
First, I would refer to the HWH Manual. http://www.hwhcorp.com/ml19048.pd
is the correct one I think.
It seems to have a step by step process for troubleshooting with some exhibits and diagrams.
Obviously, the ground attitude could appear to have the coach leaning when it is actually level. Are you determining the left front lean via the lights on the Control Panel or by measuring with another level mechanism?
Does the system vent air that you can hear, or is the electric pump activating after the rig has been leveled awhile to restore coach level attitude. In the first 24 hours of being leveled and parked, my rig will do some venting and leveling, then it pretty much locks in for the duration of the stay.
Does your HWH control panel display the green Travel Mode light when the coach is shifted into gear and has 100 psi of air pressure. If not, then it is not level and you should not move the coach.
Can you level the coach using the automatic or manual buttons so that the indicator lights display properly for a parked situation or a travel situation?
If so, you could get the coach level in the travel mode and then disconnect the fuse for the HWH. Then you should be able to move the coach. I would call HWH for guidance before doing this.
With answers to the above, I might be able to suggest other steps. Or you might get lucky and someone will have your answer by then.
A leak should be identifiable by sound or spraying the air lines and bags with soapy water and looking for bubbles where the air is escaping.
If the entire front lowers due to the leak that would indicate the air valve sticking open? My did that and a tap with a wrench fixed it. It is behind the driver front bumper.