Render target shows some objects only

Hi,

I am working on my beginner-type space game. Trying to get a second view from a camera (never mind why).
The gold ball is the “space ship”. The camera view at left top as you see shows the ship but not the sun even though it’s using the same camera. Actually the sun does flash up intermittently. I wonder if it’s a bug for that reason. As a side issue the second view is a mirror image (but not exactly as you see by the highlights on the ship).

I have got it working with a different project so I expect it’s something else in my project.

I’m using 4.13.1. 4.13.0 also had the issue.
I’m on a Mac.

OK so possibly predictably the act of writing this out got me thinking in a different way and solved it.
It’s not the same "ship’! So it’s really something else.