Using Smart Mode subtitles don't download for playlists

When I download a playlist for example:

https://www.youtube.com/playlist?list=PLdkj6XH8GYPQq29L92FbpSrzmnu97ooPf

I have smart mode set to download subtitles on English and I know the first video at least has English subtitles yet when I download via a playlist it doesn't work, if I download the song individually it does work.

I really don't want to have to manually input all the playlist entries just to have subtitles. Your software works really well and your website is supremely designed but this is a bit of an annoyance.

What am I doing wrong?