When starting a night mission in multiplayer (as client, not host), the brightness is saturated (see screenshot).
The bug occurred for me client-side, but not for the host.
Note that this was tested with just 2 people: the host, and me. Not tested with more than one client, so don't know if it would occur to just one client, several, or all clients connected. {F18647}
Might be linked with alt-tabbing, or going in the Steam overlay before starting a mission.
-Several debugging details-
The test mission was set on 7th july at 22:00 by the host, and the bug occurred the first attempt, and once again after aborting the first run then restarting.
The host then set the time to 13:00, no visual bug occurred then.
The host then set the time back to 22:00, and the bug was gone.