Video Doorbell Night motion detection

My video doorbell stopped detecting motion at night in early-October.  Before that, it worked great.  I've called tech support twice and have received two replacement doorbells.  They work for a day and then stop working.  Motion detection during the day works fine.  I've done the reset/reinstall thing with the same result.  I don't think this is a hardware problem.  I don't really want to call tech support again because their only solution seems to be to send me another doorbell.  If someone at Simplisafe that has access to the firmware folks would ask them to check the latest firmware, I would be thankful.