Put car back on lift with wheels hanging. Trigger ELC to pressurize the system (easiest way is to move the leveling arm with the ignition on, or the ELC trick used for drag racing). Lower car. Let air system vent on its own to let the rear back down. Problem should be fixed.
Do this immediately, or you can damage the shock if you haven't already (not even counting other things).
I believe what is happening is the air bladder is binding up on itself, which can lead to pinching, deformation, and/or cuts.