Computer Farts and lost music

[BASHFUNK]

Now I use spotify quite regular I've found that every hour or so a track is disrupted by a crash computer fart like noise for a second or two then continues

Now I've just opened my laptop offline to see my favourite downloaded playlists are no longer downloaded and the download option is clicked to off
Meaning I'd have to reconnect to the Internet to download again

Why????? And how can I prevent this