SR20DET Purge valve blows air out at idle, is this normal?

[QuinGarcia]

Hi, ive got an SR20det, completely stock and its on the dyno. When its idling, there is air rushing out of the filter constantly, is this normal? There is a hose running to my purge valve from the intake manifold (manifold pressure) so whenever this hose sees vacuum it opens the purge valve. Clearly this is supposed to release excess air pressure when you are cruising and let off the throttle, but is it supposed to be leaking air at idle too?