A PSS should not leak. It is likely you have a damaged rotor or graphite disc.

Occasionally when it gets burped a piece of crud gets trapped between the two surfaces creating a leak. It should NOT leak.

I would try contacting PSS. Often times they will just send you out the new vented graphite disc.. If the stainless rotor is scored this can be re-polished on a piece of glass with wet sand paper in progressively finer grades. When you get to 2k spin the rotor in a drill press on the glass/sandpaper to polish it in a rotary fashion.