Bypass notification chirp

After a drive when I arm the alarm it doesn't give me a bypass chirp. Then when I goto disarm and rearm without entering the car that's when the bypass chirp occurs. So basically the first arm after the key has been in the ignition is fine, but every subsequant arm/diasarm operation will cause it to give the bypass chirp. It's not the shock sensor sending it's signal back because the door is already closed. Anyway next weeek I will be borrowing another DEI 508D proximity sensor of my friend and plugging that in to see if it's a faulty sensor.