I have an Ultralite. It is somewhat new - I've used it maybe 9-10 nights. I have lost a few pieces of down. I do notice it might leak more when it is compressed more, but it is hard to say for sure.
Anyway, since there are about 2 billion pieces of down in the bag, I don't worry about one or two feathers coming out per trip. I'll wear out the material before the lose of down is an issue.
But, if it is bad enough to cause a difference, just send the bag back to WM.
Just my two cents :)