Redstone dust pointing into centered sulfur cube with tnt does not quite ignite it.

The bug:

Redstone dust pointing straight, into centered sulfur cube with tnt does not quite ignite it unlike Java. But cubes inside redstone dust however do ignite.

Steps to repro:

1. Place redstone dust

2. Place sulfur cube with tnt from a bucket, next to redstone dust, do not push it!

3. Activate the dust with a torch. (Torch cannot touch the sulfur cube!)

Expected result:
Cube ignites.

Observed Result:
Sulfur cube with tnt does not quite ignite