how to make kodi save subs for a movie that is on a remote resource

Hi!

so now I'm running KODI on an Android TV device. My primary use case is browsing family pictures out of my NAS, but from time to time I'd like to watch something out of my old movie collection.

SMB is not working, probably due to some Android related reason. (repeated the same steps and using same account on a KODI installed in Ubuntu works fine). But still I can get the movies play over plain HTTP.

Now to the issue. When I'm using KODI on a Linux box, I can download subs, and they stay available, so when I play the same movie again, subs are already there. When I do the same with Kodi on Android TV, the subs vanish and I have to download them again. 

In bug reporting terms:

Preconditions:
- Kodi installed on 2 devices, Android TV and Linux. The Linux box has locally stored movies, Android TV over HTTP.
- opensubtitles installed and configured to download movies.

Steps taken:
- play movie
- use opensubtitles to download subs
- watch movie a bit (subs are there)
- stop the movie
- play the movie again

Expected result:
- the subs will be available

Obtained result:
- Linux installed KODI with local movies - subs are availabe
- AndroidTV - subs are not there, have to download them again.

So the questions are:
- where does KODI store the downloaded subs,
- is it the fault of AndroidTV version?
- is it the fault of the way my movies are made available for AndroidTV? If yes, then how should I make them available for the subs to stay available? SMB does not work in the Google Play version on Xiaomi Mibox S for some reason...