Sheets can be a tad confusing when you have them loaded up with views. Don’t forget that sheets themselves are views also.
What this means is that the sheet will have its very own Visibility Graphics settings. The Sheet’s settings do NOT override the settings for the views on that Sheet. So you can’t turn off walls on the sheet and expect to not see walls in your views. You need to go to each view and turn off the walls there.
So, be sure to pay attention to what Visibility Graphics settings you are changing. I have seen several occasions when the settings for the sheet were changed when the individual thought they were changing the setting for the view. It was chaos! It was madness! Dogs and cats, living together! (Not that bad. But we did scratch our heads for about a minute.)