Why does it seem like air only enters the shock with the RENNKOMPRESSOR SUSPENSION when the pump rod is pushed all the way down?

Before air can enter the shock, the RENNKOMPRESSOR SUSPENSION first has to reach the pressure that is already present inside the shock. Only once the required pressure has been reached does the check valve open and air flow into the shock.

This can create the impression that air only enters the shock towards the end of the pumping movement.