Null obejct linked to the camera doesn't work

There is no bug. It's a user error. You are either not looking at the Active Camera or not following the correct workflow. When you are having problems with a tutorial please post a link to the tutorial. Most of the YouTube tutorials are presented by enthusiasts that don't really know how to explain or even do things. You have to vet your trainers. The number of views is no indication of tutorial quality.

If you want help diagnosing your problem we need a full screenshot of your comp embedded using the toolbar or you can drag images directly to the reply field. Please don't use the "Drag and drop here..." panel. It's buggy and hard for us to use. To prepare your screenshot make sure both the switches and modes column are visible, the comp is selected in the Project Panel so we can see the settings, and all problem layers have been selected and the "u" key pressed twice to show the modified properties. 

You might want to check the User Guide. There are some decent 3D tutorials there.