All the voices of my P08 are panned very slightly left or right of dead centre, so I know there is a degree of hardware calibration of panning that goes on with voices. Sounds, to me, like your voice 8 is wildly mis-calibrated, which is a hardware fault.
As Sacred Synthesis says, the good people at DSI will sort you out.
With my own instrument, I've actually come to like the slight panning imperfections and the character it gives me. Of course, your fault is much more severe and I've no doubt you will get it repaired.