I have noticed strange lighting issues on east facing walls. Normally the wall (pictured in screen shots) at night doesn't illuminate even though there are torches near by, during the day I have found the same section now showing up as black.

I can upload this world to drop box if you require it for your debugging.

Thanks,
Baski

PS I searched for other issues, but was not able to find another open issue with the same issue (but I did see a few issues with blocks east of a hopper, not sure if they are related).