Creative question

I’ve got a question.

In creative 1.0 when working on a map what would cause certain things to disappear after 30 or so minutes, but function like they are still there?

Here’s a short video showing the problem.

I remember a time at least a year ago when this did not happen no matter how long I was in my map, but a Fortnite update caused it to start.

Further information.

When in a baller I can pass through walls that are there and not showing, but when flying around I cannot pass through just like it is when the wall is visible.