Decided to Log out in the new underground tunnels of Nasdara for a night, logged back in and the tunnels were perma bright, decided to exit the tunnels to group up with my pal and we went back in and the tunnels were still perma bright. He said they were pitch black for him so this is a very game breaking bug.

Find a tunnel ladder.

Go into tunnel.

Log out > Log back in.

Tunnels are perma bright for the rest of the run.

Unknown if the other tunnels are bright as well or if its stuck to one specific tunnel.