Hmm. I haven't waited to see if it stops after a while. I will see.
Having had the ICV out today and cleaning it, I am wondering if it's simply a side effect of the design of the ICV - the way it restricts/controls airflow. I'm not sure how other ICVs work, but I know the Denso type don't look or fit onto the manifold like this. If I remember rightly the Denso one is a plunger that goes into a specially constructed crevice on the intake manifold/plenum, whereas this type is just a straightforward restrictor valve plumbed into a hole in the side of the manifold.
The noise isn't noticeable when driving. I just want to be sure that everything is as it should be. I haven't had the car long and have had to replace quite a few things on it right away.