I have been getting frequent, roughly every 10 minutes, CMC videos every night for the past 3 nights. If you look at the very start of the attached video you can see motion is being triggered by an increase in light intensity.
At first I thought it was headlights. But this was too regular and was ALL night long. It was not our front door lights. They are on a photosensitive sensor and the whole building goes on or off based on that sensor.
Turns out there is a street light that is doing some weird cycle thing where right at the end of each cycle it gets really bright then turns off.