Should subtitles work on the free iPad app?

Just that really.

Recently been burned splashing out on apps that don’t work as expected so I’m in definite try before you buy mode.

So, scenario. Playing a movie locally stored in iTunes on iPad Mini 4. No subtitles. Go to subtitle settings on Infuse and “Get More”. Select subtitle of choice from list. App then shows subtitle (en) with a check mark against it. Play movie again. Squat. Nothing. Try with different subtitles. Nothing.

Another app tried where something DOESN’T work. Check.

Should it or shouldn’t it work. Any more settings I should set? Or do these subtitles only work if they are downloaded to a folder that the movie is streamed from, not if you play direct on the device?

This used to work but something (perhaps at opensubtitles?) must have changed because it no longer works. I’m using iOS and tvOS versions of infuse.