Lighting is such a pain. Between that and navmesh setting up/baking, probably the most time sucking part of making a game imo. I spent like a whole day googling trying to find out why my scene was never truly dark. I think the final issue I ran into was that the game was doing a quick bake when I entered playmode, allowing some slight lights and shadows to sneak in. So I had to rig the scene up so that all the lights started turned off (including the point light attached to the player), and then were only activated once the game had started so their lights didn't get baked. I don't know if other engines are this picky with lights, but Unity irritated me with this one.