Pusher Axle operation Question

Construction company owner I drive for part time bought a 21 Pete 567, 20 yd Ox Body with a pusher axle with less than 100k on it. Here's the question. When the regulator on the control tower in the cab has air pressure dialed in on it, and the axle lower raise switch on the dash is in the up position, with brakes released, the axle is up. (There is also a gauge on the dash showing pressure of the pusher air bags.)
When ever you apply the parking brake, the axle will drop and the air bag pressure will rise to the amount set on the control tower gauge by the regulator. When you release the parking brake the axle will raise. If you push switch down, axle will then lower.
When driving you can raise and lower the axle with the dash button normally. If there is no pressure dialed in with the regulator, the dash button has no affect on anything.
It does not seem right to me for the axle to drop or raise every time you set or release the brakes, is this something new? Is something plumbed wrong by the body installer originally maybe? He has another truck like it but older and it doesn't act this way.

 

Hmm. That didn’t cross my mind but I bet that’s it. Thanks!

 

Other truck raises when put into reverse like that. It is also steerable to boot.

 

Thats exactly what it seems like to me. Reverse has no affect on it

 

I suppose it could be that as well. Ill try to look at these ideas and see whats goin on. I thank yall for your informed responses..