The torch is showing light only for the one that uses it (lit up), and not for the others.

One can use this exploit to light up the area around him and nobody sees you using the light. It's like you have a small area night vision only for yourself.

I've added two screenshots from two different players perspective.

Name:  torch bug 1.jpg
Views: 15
Size:  15.3 KB

Name:  torch bug 2.jpg
Views: 15
Size:  5.4 KB

Hope it helps