I don't know if anyone else does, or if this was just a fluke. I got my stuff from a Home Depot--it's made for gardening. All I know is I'll be boiling all moss from now on.
Once two eggs were definitely dead, it was easy to pick out which ones were going to die. When a weird kind of mold-ish stuff (looked a bit like cigarette ash) and a black coloring starts to cover the egg, it's too late. They get soft, and eventually shrivel up if you can't/don't remove them (all but two are stuck to good eggs). I almost tried listerine, but I didn't come across the suggestion soon enough and forgot about it when the mold overtook the last 3. 11/17 stayed good, though, in the stuff, which I would say is pretty good odds since the first 3 started going bad in the first few weeks.
The reason I don't assume these eggs were bad from the start is one of them in particular had the most obvious veining one week into incubation. It was very obviously fertile and I thought looked like probably the healthiest egg in the bunch--until it went bad (4th or 5th egg to go).
Anyway, like I said, I don't know if it's normal. I don't think it is normal, since I have never heard of it (haven't done too much looking, either, really), and never hear "boil the moss" suggestions. I'd say boil the moss to be safe, but keep in mind that I have no evidence that it was strictly the moss's fault.