Question Why does the cross appear when the camera is backlit by the Directional Light?

[TI_vam]

Why does the cross appear when the camera is backlit by the Directional Light, and why does the cross disappear when the Directional Light is turned off, and why does the cross follow the Directional Light when the Directional Light is turned off, and why does the cross follow the Directional Light when the Directional Light is turned on? How can I turn this off?

 

[TI_vam]

I suddenly had a flash of inspiration and used the Embody plugin and the problem was solved. So this question is just to know why.