General Particle Source produces a discrete spectrum

I have been using GPS to generate power-law spectra of primary electrons in a simulation. Recently I’ve been inspecting the spectrum of these primaries and discovered that GPS doesn’t seem to produce a truly continuous spectrum. Instead it seems to produce a discrete spectrum with peaks every ~keV or so. Is this normal behavior? If so is there any way to increase the “resolution” of GPS without resorting to using a user defined spectrum?