As MC-45199 is WAI, this is therefor an issue. An empty grass texture won't fill the pixels, whereas MC-45199 says they should.
If the grass texture is completely made of Alpha, it does not fill with opaque pixels to avoid x-ray hacks.
MC-51579 Some solid blocks will still render transparent with an X-Ray resource pack
MC-45199 Empty Carpet texture pixels no longer Transparent (also true for all blocks)