Indeed. That's the solution. Initially it picks up a tremendous amount of static noise when you open the intercom. Highly distracting and annyoing.
All you need to do is just adjust the GAIN. Open the intercom and with a small screwdriver from a sewing kit or so and turn the GAIN down. You'll usually find a very small opening under the mic muff. Doing it this way gives you a good idea of the peace and quiet afterwards. I only found this out after using it online for one year. Now I sometimes find myself going for the intercom open switch when in fact it's already open. That's how much difference there is!
I also noticed that on some of our aircraft there's more background noise than on others. It also varies a tiny bit by what headset the other guy is using.
P.S. I use my own Sennheiser HMEC 25KA(S) ANR Headset and am really pleased with it.