Robert,
Yea, that was me. I had a couple of low spots on one fillet (on top, of course) and I was just too lazy to mix up more SuperFil to fill them. So I foolishly put some light weight spakle in the low spots. I did film them with CA, but I suspect I sanded through at some point. Sigh... Live and learn.
Ended up having to dig up the entire fillet, hit it with some catalyzed glazing compound (what I should have done in the first place), sand it out and reshoot the area with paint. Came out fine in the end, but it was a lot of extra work because I was lazy that day.