The microlenses on the ASI1600 do a small checkerboard around the brightest stars. You can reduce the amount if you focus a little to the inside (vs. outside) and be aware of temperature changes. Also it tends to happen more with the O3 filter than others so you could use shorter exposures with that channel or be aware during stretching. It is possible to remove the stars during processing and re-add them with less stretch later. Startools ('heal', 'layer')
Now the large halo that is off center indicates a colimation/centering problem. The star should be centered on the shadow and the halo should be balanced in width top/bottom and side/side. If collimation was good initially then tube flexure during the exposure is causing issues.
The half moon halos are likely due to a reflection somewhere in the optical train. Check for any unpainted surface, like edge of secondary holder, tube side walls, focuser, spacers in the imaging train etc. They seem to have the same size as the central halo and in between the vanes so they are like due to reflective cylinder.
Hope this is helpful.