Hi, here is sample. I made a self illumination object on the back of normal object.
In Enscape, when camer can see the self illumination object, it seems normally.
But when camera can’t see the self illumination object, it seems not work.
You are not alone. 
For me one of the most important issues.
Is the self-illuminating material applied on both sides of the face? If it’s on the backside only it won’t illuminate the scene when not visible to the camera.
@Micha in this case I assume the issue is different, as the scene & especially the emitter geometry is very simple.