Saving level messes up lighting


Whenever I save a level as a new file, the lighting messes up. The scene suddenly goes really bright.

A few things annoy me when saving.

The camera seems to jump to another location
Lights, reflection casters etc that were hidden, turn on.
Objects in the scene that have been turned off to speed up the level turn on again

Can anyone help me with this?

The most important thing is the lighting. It’s as if the scene has been set to unlit but only rebuilding fixes it, until I save a new level.