I assume you have performed the air brake pretrip test to determine that the compressor and brake system connections are functioning properly and retaining air pressure?
If so, you can probably focus on the air leveling system only.
Does your electric compressor try to maintain level when the rear bags start to go soft?
Are you able to level the rig with the leveling system?
Can you hear air escaping under the coach once it is leveled, without dumping the air) and just sitting? (I would guess not if you were spraying soapy water under the rig.)
If you cannot level the rig, then I would suspect the leveling air solenoid.
Because two bags deflate, I would think it is not likely leaking bags, but I hear they are cheap to replace.
If the electric compressor (in the front utility compartment) is not working then perhaps it is also a source of the air leak.
If you have sprayed soapy water on all the air line connections and found no leaks, I would focus on the solenoid or the electric compressor.
1995 CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs