Tell us about yourself!
As with most natural fluids, smoke should take the path of least resistance. The bricks are much tighter than the path of flow you created with the open bricks. As long as they remain unobstructed, the air should "choose" to flow through that pathway. Get a few cookouts and grease popping and you'll probably generate some sort of "meat mortar" that even further seals the edges.
Have you used a light meter to measure exactly how bright these are?