In 5.0.3, I removed all light objects from the project, including the skylight and any/all lightbulbs. Yet, there are two spots of light in my model, one on the floor and one on a wall. What might be up with that?
The same thing can occur with shadows.
Rebuild the lighting to rebuild the lightmaps and shadow maps in lightmass.
If you are running lumen, this is a bug if it occurs when running the game. If it happens in editor after running PIE, moving the viewport "camera" will recalculate the lighting.