Did you recently change the programming on that motion sensor?
I am showing that Zone 16 Motion Sensor is programmed as Group 25 Safety Motion. This sensor does not report or trigger an alarm. This is a chime only sensor when “Activity Monitoring” is active, regardless of panel status. I am showing recent status in Alarm.com for both motion activity and tamper.
While Motion Sensors can be used in Smart Arming they must be in either group 17, 20, 44, 43, or 35 . A run down of motion sensor groups and how they function can be found on page 71 of the manual here.
Additional information on Smart Arming can be found here:
AS far as resetting, what model of motion sensor are you using?