By using the slingshot loaded with Freeze Rounds, you can shoot at a lit Nightmare Light to extinguish it. Doing so however will cause all players to lose connection to the server.
I've uploaded a video showcasing this bug here:
1. Play as Walter
2. Equip the slingshot
3. Set Freeze Rounds as the ammo for the slingshot
4. Place a Night Light/Fuel a Night Light
5. Extinguish the Night Light via shooting it with the slingshot loaded with Freeze Rounds.