Leaf blocks surrounded by most full blocks lose transparency when a slab is placed on top

Steps to Reproduce:

1. Place a leaf block
2. Surround all four sides with full blocks
3. Place a top slab on top of the leaf block

Observed Results:
The texture of the leaf block becomes opaque.

Expected Results:
The texture of the leaf block should remain transparent.

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Original Description:
I placed a quartz half-slab onto the upper half of a block and the leaf block below it changed it's texture. instead of the gaps int the leaf's texture being transparent, hey changes to a solid light green color. i was also playing on the latest update to Minecraft Windows 10 wit hthe option of experimental gameplay on.