I am working from a Bortle 4 sky area and when using the focus module, sometimes it appears to work properly (verified with Bahtinov mask) and other times it ends up reporting that it has focused but I end up with donut stars. I would love to be able to use this but I just don't have confidence that it will give me a good result. Has anyone else seen this? For example, last night I started imaging with manual focus and then about 1.5 hrs in, I used the autofocus module and it worked fine. A few hrs later, I used it again, the stars looked OK and went back to bed. Turns out all my images from that point on were no good. Help?