Observers act as transparent blocks with redstone wires

The Bug:

Observers act as transparent blocks with redstone wires.

Steps to Reproduce:

1. Build the setup as shown in the attachment below. setup.png
2. Place a redstone block on top of the diamond block and watch the redstone lamp closely as you do this.
3. Take note as to whether or not observers act as transparent blocks with redstone wires.

Observed Behavior:

Observers act as transparent blocks with redstone wires.

Expected Behavior:

Observers would not act as transparent blocks with redstone wires. Instead, they should act as solid blocks.