Flowing lava is invisible when looked at through a specific setup.

How to reproduce:

1. Place a barrier on a platform that is at least 3 blocks wide, 5 blocks long and 2 blocks deep (normal flat world works fine).
2. Make a trench that is 1 block wide and 3 blocks long, with the barrier as centre (barrier is above the trench, not in it)
3. Place a block on top of the barrier from step 1.
4. Place 1 blocks to both sides of the block from the previous step. IMPORTANT: place them in the opposite axis that you built the trench in, so that when you look at it from above, your build looks like a cross, using both the trench and the placed blocks.
5. Remove the block from step 3.
6. Place a lava source on top of the barrier from step 1.
7. Let the lava flow.

Observed results:
The flowing lava is not visible through the barrier if you look at it from the side.

Expected results:

The flowing lava is visible through the barrier if you look at it from the side.