Resetting and reentering the activity zones appears to have made a difference. On the three days before I reset the zones, I had 7, 5, and 8 triggers from movement in the grey zones, whereas the last two days after resetting the zones, I had 2 and 3 false triggers respectively. It’s not a big sample size so could be a statistical fluke. However, I think I can live with it if it is only 2-3 per day. I would rather have a few false positives than miss any real motion on my porch, and as far as I can tell, my camera has caught every real event with 100% accuracy. I should also add that the false positives are fairly rare. There are probably a dozen people walking or driving by every hour, and most of those are successfully screened out.
I will continue to keep in mind that firmware updates can mess up these zones. I am currently on 7.75. I’m not sure what I started with, but have only had the camera for a week.
Joel, I appreciate your hint to point the camera away from the street. However, I have good reasons for pointing it this direction. One reason is my wish to record the face of anyone standing at our door.