Where's all this light coming from?
I built an underground mob spawner in 1.8 SMP that I can turn the lights on and off in. I used pistons to move glowstone over glass holes in the ceiling – whenever the lights are off the holes are covered.
But…there’s light coming in from somewhere! The rest of the room is solid cobble or smooth stone, so I can’t figure out why there would be so much light! How can I seal the room in darkness?
3 Solutions collect form web for “Where's all this light coming from?”
I saw this bug in some version of 1.8, I think (but in the form of torches placed underwater leaving light behind). I didn’t find any way to fix it.
It’s fixed in a 1.9 prerelease.
Is there possibly lava nearby?
In my experience, light from lava ignores line of sight — at least as of 1.8.
I have encountered this before. Kevin Y is correct. It is a lighting glitch which should be (and for me always has been) fixed by placing a few blocks in the brightest area and breaking them.