I recently grabbed a bunch of DVD quality episodes which contained both the video as an .avi file, and a DVD .ifo file. I also already had these episodes as DVD quality .avi files.
Drone deleted each existing .avi file and replaced it with just the .ifo file (which is tiny, only about 132 KB).
Luckily I’d enabled the “Trash folder” option, so the deletions of the .avi files weren’t really deleted and I was able to easily copy the files back to my NAS box.
I’ve only seen this behavior with .ifo files.