Plex Media Scanner is scanning TBs of data, but is not set to scan periodically or automatically...

I noticed my external drive where I keep media was blinking, but no one was watching anything. I checked to see if anything was transcoding, but it was not. I also check if there was any scan occurring, but there was not. I also have it set up to where I need to manually tell it to scan the library. I opened Activity monitor and saw that "Plex Media Scanner" was reacting TBs of data from the drive. Is this normal?