Dear ZWO,
When I'm capturing a star mostly of A or B spectral class and of middle brightness, after about one minute of exposure an ugly green halo appears around it when the star should be blue hued. Maybe it is a bug since the version 2.6.0. Though I increase the saturation to +50 to obtain realistic color for the stars, the green halo was not present before. Have you changed something in the color calibration?
You can see it for example in this picure:
I cropped the center of the imagee to see it better:
