Ring Doorbell 2 notifies me of phantom motion

I've had a Ring 2 installed for the past six months or so and have loved it until recently. I've been getting a lot of notifications, especially late at night, when there doesn't appear to be any motion. I installed the Ring 2 doorbell on our front gate (battery powered). We have a long driveway and the Ring 2 detects motion over much of the lower portion. Some of the notifications we've gotten in the middle of the night have been warranted. Like the spider crawling over the lens. But, we have recently been receiving notifications when there does not appear to be any reason (based upon reviewing the video and looking outside). We also have a motion detector light nearby and it hasn't been tripped during these Ring notifications. Any thoughts? It hasn't happened until recently. Also, how does Ring handle rain in respect to notifications? I'm in Southern California, so we haven't had much rain since I installed it. The Ring seemed to do okay with the heavy winds we had recently without false alarms.