This is because there are many lightswitches bound to certain light groups, if the map had static light it would be fixed. But I want to keep lightswitches for more realism and roleplaying purposes. If props appear to be black in certain rooms you should switch the light off and on again, this should make the props in the room appear normal again.

There is a fast way of fixing the lighting of props without turning on every single light at a time...
In the garage, there is a power system that can turn off every light or turn them on, if you switch it two times, the lights will flicker and props will be fixed.

Just take the light tool and place lights around the house hope it helps