So today i made a Renderman Hunt.
First i took a picture of a build but nothing.
(They say he appears after you take a picture of a just-finished build.)

Nothing.
But then i noticed something on the bed.
It was nothing
Just a player's light.
But there wasnt a brick to spawn it.

So i pulled out a wrench to see if the brick that spawned it was invisible.

Nothing.
Then it disappeared.
Later i tested to see if lines showing an invisible brick actully show up in pictures.

They easily do.
Then i took a picture of where the light was.

It was still gone.
What happened..