Seeing that the gate is open whilst you are at idle backs up what I said about a 2 piston DV, in the idle position the main piston floats in the mid position whilst the 2nd piston keeps the intercooler side sealed off. I think the spare spring will make no difference, you need to change your DV to a decent 2 piston one or the factory recirc, if you want a good 2 piston DV Forge do a good selection, if the one you have fitted is a Forge (cant tell from the vid) then it should really have a 2nd plastic piston and small spring.
Cheers Iain