Lights get darker when loading scene

Seems to do the trick, but only for the loaded scene?

Yes, only for the scene you just loaded via API. I was having this issue when I loaded the scenes like this.

Hmmm, I bumped into the issue that Stencil buffer is not working properly after "Generate Lighting" ...

Hehe, this is funny. I actually had to do the opposite for mine to work. I checked the box that said 'Auto Generate!' That fixed my issue. It created a new Asset in my Project/Scenes named New lighting Settings. It was bright! So I adjusted the light settings brightness, in my directional light in the Hierarchy, via the the Inspector settings. Problem fixed! For me, this issue happened in Unity 2020.3.21f1. While working on Prototype-5, of the Unity Junior Programmer pathway. | P.S. I did this before I spotted this thread. I guess I am learning how to code! I wish I would have found your post sooner, it would have saved me one hour from my 'life span!'

This of course gets rid of the missing environment lighting issue, but unfortunately it does so by removing the lighting contribution of the environment. While this might work for some games or some scenes and for averting a complete catastrophe, it's not a solution, it's really just a disabling of the feature, which is not really acceptable on Unity's part.

Unity needs to fix this very basic feature, even if it's only affecting the editor, which there is no guarantee that it is. Environment lighting cannot just be left up to a gradient, not for most modern games.

But it is an option though, and it does at least circumvent this very serious problem for testing purposes.

It will fix it, and it's good. But this will set the lighting for your entire scene. It will make your rooms, caves, and other environments that you might want darker, equally light. This setting affects the entire environment. This problems might need to be fixed in the lighting section, in order to maintain control of the different illumination settings that we want in a scene. But if's a side scrolling runner game, then you're OK. Still, you get props for creativity! --> This setting is for the 'Master Scene.' this means it affects the entire scene. It's used for real time and **Global illumination. | Not telling you this to prove you wrong. But so you know why your entire scene might end up looking brighter or dimmer than you want it in certain locations. But who knows, there are many ways to bypass these settings. You taught me something. I only knew about local illumination before hand!

This seems to happen when the load scene has a different lighting setup than the second scene. It also seems to be that the scene you are in when you build, is NOT the scene that gets lighting set.

I dont know how else to explain it.

I have a menu. I have levels. The menu is the first scene and has no light. when I build from the menu, all is well. When I build from any other scene, the build has darkened lighting.

This is a very weird and confusing issue that needs resolution.