I can't say that I have, but I have noticed that the subtitles always seem to be switched on when I watch something new now.
What platform are you watching on?
What are you using?
I'm watching on my PC, so I can't really help you. All I can suggest is the usual stuff: Make sure everything's up to date, you've not accidentally muted anything, etc. If it's just newer videos that are having issues, it may be a temporary thing.
My audio issue recently has been the audio way out of sync with the video. I have a fairly unreliable internet provider but in those instances the picture was mostly perfect - but the audio not so much.