I looked into the "Encyclopedia of Materials Characterization" under Auger spectroscopy. It lists artifacts in the spectrum, but I am unsure when you say "core-level loss peaks" what is meant and would need to understand it.
The secondary electron (energy) distribution typically shows a broad peak at lower energies, known as "true secondaries" - e.g. a result of scattering and interactions while escaping the sample; then are the small Auger peaks, and to the right (high energies) is the elastic scattering peak of the incident electron beam.
Does this make sense?