This is the documentation for Enlighten.
Turn off Enlighten updates in game
To turn off Enlighten updates in game, set the Default Update Method in the level properties to Static.
With this setting, when in game mode, the lighting appears as it did when the level was last saved.
This eliminates the cost of Enlighten updates, and is ideal for areas where the lighting doesn't need to change in-game.
You can only see the effect of this property in game mode.