I have got my subtitles switched off (English language, English subs).
I noticed, that they get switched back on though in certain cut scenes, e.g. when I arrive to the Arch and the Elder starts talking. They don’t just reappear for that cut scene, but they get switched on in the settings again entirely, against my will 
That means I have to got to the settings and switch them off again.
It happened several times by now the same way and I did not see this bug reported yet.
I finished the game and it happens all the time - but not always - in cut scenes.