This issue started to happen when I added light probes to my dynamically lit scene. When I tested my multiplayer game with other people, me (and they too) experienced a bug when sometimes when a player respawns the scene loses all lighting information. Dynamic objects turn pitch black with no lighting at all and static objects only get direct lighting. The bug does not happen constantly, but this is game breaking, since my weapon's scope uses an emissive semitransparent material that turns into a giant black blob too. I think this has something to do with adding lights (muzzleflash) or turning cameras on or off (player instance camera turn on or off depending if that is your player or not). It'd be nice if someone else who has experienced this bug can add some information. Keep in mind that it happened on Unity 5.0.0f3. I just installed the latest Unity 5.1 version and will report if it happens again.