Because barrier blocks are transparent, it is expected that the blocks/chunks behind them will load.  Unfortunately, I have found that an x-ray effect occurs when using one or multiple layers of barrier blocks.  For example, I created a stadium with a barrier-block-enclosed arena in the center (1,2).  If I stand at one side of the stadium and look through the arena, a hole appears in the other side of the stadium (3).  From another angle, I cannot see inside the arena at all, until I approach within ~20 blocks from it (4,5,6,7).  Fortunately, I was able to reproduce this issue in another world.

In order to reproduce this loading glitch, I created a new superflat world and built three parallel walls in the sky.  Note that this issue does not occur in close proximity to the ground for some reason.  However, the glitch can still occur at low elevations if the ground is removed in the region.  For this example, though, I built the walls in the sky: two of them were 50x50x1 barrier block walls, and the third was a 50x50x3 oak log wall (8).  After reloading the game, I noticed that the barrier blocks cause the oak blocks behind them not to load (9).

I have attached the Minecraft world with the sky walls for reference.

Thanks for the help!