All of my lighting automations that turn on a light upon motion, and then turns off the light after inactivity stays that way are not waiting the full wait time. Instead of the 15 minutes specified, the lights go off after about 15 seconds.
Right .. that's what the log shows. The light stayed on for about 15 seconds only because the motion sensor didn't report inactive until the active had cooled down.
It's completely reproducible and occurs on all my similar automations.