I downloaded a couple of TV episodes early this morning. They finished downloading at around 2:30 AM. When I woke up this morning about 8 hours later, the Plex Media Scanner was still running on my Mac and was using close to 200% of my CPU. I've attached a log that covers all the activity from 1:40 AM to 10 AM. Specs:
PMS v0.9.14.6
El Capitan v10.11.2
Mac mini (Mid 2011)
2.7 GHz Intel Core i7
8 GB 1333 MHz DDR3