It will be worth while emailing Atik support.
My guess, based on several reports and writing the ASCOM driver for Atik, is that there could be some threading problem and that checking the CCD temperature during an image download could cause a problem. Unfortunately I don’t see it with my system.
SGP pulls no punches and does a lot of multi-tasking so it’s particularly prone to this. In particular the CCD temperature control/monitoring seems to be running in a different thread to the image acquisition and download. The problem seems to be associated with reading CCD temperature during an image download.
The released ASCOM driver locks so there should only be one command active at a time but maybe that’s not enough. I’ve tried adding more locks so that CCD temperature reads can’t be done at any point in the download process. I hope this will help but there are limits to what I can do, especially as I don’t seem to see the same issue myself.
I’ve contacted Atik about this but I think they may not be back until next week. I think it will be better to go through them for this, they may have other ideas about what’s happening.
The other thing that could help is if SGP were to be less enthusiastic about using multiple threads. I realise this should not be necessary but it could help.
Please bear in mind that I’m not speaking for Atik. I developed the ASCOM driver for them some years ago and that’s all.