The placement of Glowstone Lamps provides asymmetric, and thus, unexpected behavior. The wood blocks are half slabs on the same layer as the glowstone lamps.

Notice that the pattern is symmetric , but some blocks fail to light.

I browsed for this and I appear to be the first one to report this for the lamps. This one is very obvious though. I hope that doesn't mean that bugs in redstone behavior are not considered as authentic/true bugs.

In the meantime, construction on my build is on hold until this is fixed.

Thanks,

Tim Legg