This app was mentioned in 5 comments, with an average of 2.60 upvotes
Well this is Android
https://play.google.com/store/apps/details?id=il.yavji.volumecontrolads
This one seems good too but it has ads
Same problem. No fix found yet.
Edit: Fixed with this app: Volume + (Easy Control) Free
install:
https://play.google.com/store/apps/details?id=il.yavji.volumecontrolads
select the symbol of a speaker with a slash. no vibrate; no sound.