Another problem, but not critical. (Fallout: New Vegas)

Everyone is healthy! Maybe someone knows what this effect is, a bug, or something like that? It looks like someone turned off the lights in the whole game world, the picture becomes cloudy, that you can't even see what's there beyond your nose. This happens almost every hour or half an hour, and it takes only 20 minutes, and at the Freeside and Lucky 38 locations, when you want to go outside, the screen just darkens and so it costs 1-2, but the sounds still remain like from the radio etc., and the computer simply refuses, does not respond to any buttons, even the dispatcher does not want to be shown. Can someone do something like anti-flight and anti-hang like on Fallout 3. Thanks in advance!