W1MUC , thanks a lot for your post.
When I make a material emissive, it seems to be pretty light stable already, so in order to faithfully file a corresponding feature request, is there any chance you could briefly pass me the project, or a project in which I can reproduce this "unstable lighting" behavior? 
Thank you so much in advance!
It used to be that emissive sources only emit light if you can see them; this seems to have been fixed in recent releases.
You might also try ticking off 'auto contrast' and 'auto exposure'.
W1MUC , could you please also make sure that you're using our most up to date release of Enscape? As Gadget mentioned, we've improved this behavior in our recent releases already. Thank you in advance, looking forward to your feedback!
Auto Contrast is off, auto exposure turns the emissive off and the scene is dark.
Ok I got it now. It´s really only about 'Auto Exposure' off.
But if turned off, the emissive has to be much more bright to be still visible.
But now brightness is stable, wherever you are.
Thanks!
Happy to hear that. Let me know if there is anything else you require assistance with!