The bug

Certain blocks "save" sunlight, emiting it even after the original source has been removed. This creates an annoying glowing spot and is very difficult to clean up given that the blocks are not obviously the source of the glowing (and that it can chain between multiple of them).

Affected blocks (may be incomplete)

• Water
• Leaves
• Cobweb
• Magma
• Lit redstone ore
• Lit furnace
• Powered redstone lamp
• Glowstone
• Sea lantern
• Jack-o-lantern

Reproduction

1. Build a sealed room without any lights in it with a single layer between it and the sky.
2. Place one of the effected blocks on the floor.
3. Break the ceiling block above that block.
4. Replace the ceiling block.
5. Observe that the room remains lit, despite the lack of a light source.

Notes

• In versions prior to 1.7.2ish, this also affected other blocks (for sure glowstone, lit redstone ore, lit furnaces, and jack 'o lanterns — mostly, blocks that exhibit MC-102162 but also similar blocks that emit full light). In 1.7.2 it was fixed for those blocks. Incidentally, 1.7.2 had a fix that removed an x-ray effect when inside of glowstone; it's possible that those are related. this issue returned for 1.11.2
• Lava is not effected, despite also being a fluid.
• Water only finicky about being affected; if it's in a pit it doesn't get affected but if it's above the ground it is.
• This only happens when the block is in direct sunlight; if it's next to the sunlight but not exposed to the sun it doesn't seem to happen.

Demos

Demonstration from the Minecraft version 1.4.5 : http://youtu.be/8nTd1KbbrLA

EDIT SEPT 19 2015: Demonstration from the Minecraft version 15w38b: https://youtu.be/bPUdssOvU78