Water bubbling from RO airgap valve after adding permeate pump

[Glenn Griffith]

I thought the brine line might be restricted and was able to flush it. It's oversized and drains into a water tank, used for irrigation, by gravity and is flowing normally. I replace the airgap valve thinking it might be partially restricted but no change. A few months ago I did replace the filters, membrane, and flow restrictor to match the rating of the membrane but the water produced is about 50 GPD and not the 70 advertised and the flow restrictor is a 70 GPD, could that be the problem? The pulses of water leaking appear to match the rhythm of the pump.