Automatic subtitles scrapers are running into obnoxious 102 byte advertisements from opensubtitles.com instead of valid .srt files. To find and clean them out, run:
find . -type f -size -200c -iname "*.srt"
Once you’re sure of the list of files shown, you can delete with:
find . -type f -size -200c -iname "*.srt" -delete