I think you have to pack the sausage on pretty thick. I've made them a few times--best stuff on earth, especially if you use hot sausage--and I've never had the problem you mention. The only problem I've encountered is getting the stuff to stick at first; the eggs have to be really dry.

A small bit of bbeaten egg and a slight dash of bread crumbs might bind everything together better. I've never donw that, but I'm pretty sure it will work.