How do I add a scene to the build without it being loaded automatically?

I have added a scene to the build window.

When I launch the game - it works great! Only the first scene is loaded.

Then I finish some configurations in my Launcher screen, then hit “Load” to load my managers, then LoadScene additively to add the scenes the user requested.

somehow it’s loading scenes that were specifically not requested to be loaded, but existed in the build. WTF?

I discovered there was a script loading a scene by build index instead of name. That resolved the issue.