Hey Critters,
That's a calibration issue, we have contacted Luxima, the image sensor manufacturer, and they suggested adding 3-point calibration to fix the issue. We're currently using 2-point calibration. This is high priority on the list of things to fix.
Basically, due to variations in the semiconductor production process, some pixels have a response that is non-linear, with slightly less response when dark compared to in brighter light. As a result, they need more gain applied, but only in dark areas. The 3-point calibration will do this.
To minimize this for now, try to avoid using analog gain as the problem is worse at higher gain, and expose your images as bright as possible to bring up the pixel levels. Applying gain afterwards will also make the spots more noticeable.
David