Strange air pump like sound from the hind quarters

[jeep]

I heard a strange sound from the rear passenger side wheel well. It sounding like a car battery operated tire pump. The car was parked and I had removed the keys. Usually when I park the car and get out I hear a hissing sound which seems to be the suspension readjusting itself, but this was different.

After giving it a few mins, and the sound had still not stopped, I started the car again, put it in reverse for a bit and then parked back, the sound was gone. Anyone else seen this issue? Can it be the electomechanical suspension component (I have the sports pkg). It may also explain the high battery drain someone else was experiencing.