Hi. I created a new blank project and created some walls by duplicating the default floor. And at first I didn’t have the issue. However, what triggered it was to enable Force no precomputed lighting and building the level.
In the reflections view, almost everything turned black, or there was something not black in the corners and by moving the camera, they turned permanently black. But in Lit view it was better.
In my original project I also had Force no precomputed lighting on, so it seems to be related with that. In 4.8 there was no problem with this.