I have noticed that when viewing some experiences that use small spaces, floors, ceilings, walls, and objects within can disappear when viewed at certain angles.
In my house in my Real Estate Plot experience, when I walk into the bathroom, the floor derezzed.
In the last room of the wonderful and atmospheric experience https://atlas.sansar.com/experiences/ria/little-giant parts of the bed flicker in and out of view as I scope the room, also the table in the middle of the room does not rez, the notes are floating.
It would appear that near clipping is set too far so the geometry is clipped.
I have tried different settings without any change.