Running Flexget on a Raspberry Pi, it has been set to download everything to the USB drive. This works, but some files are downloaded to the /home/flexget folder. This blocks the RPi at some point because the SD card is full.
Tracking down the files that appear in the Flexget folder, it seems to happen only when convert_magnet fails.
2017-07-20 02:29 ERROR convert_magnet download-series-discover Unable to convert Magnet URI for entry Friends.With.Better.Lives.S01.720p.WEB-DL.DD5.1.H264-NTb[rartv]: Timed out after 10.0 seconds trying to magnetize
2017-07-20 02:29 ERROR entry download-series-discover Failed Friends.With.Better.Lives.S01.720p.WEB-DL.DD5.1.H264-NTb[rartv] (Magnet URI conversion failed)
So after failing, the file is being downloaded, but it doesn't appear anywhere else in my log file so it is not being sent to Transmission, it's not being renamed/moved.
It seems to me, after magnet conversion fails, libtorrent will continue in the background and actually download the file.
I would assume the expected behavior is for Flexget to terminate libtorrent when convert_magnet fails.