Double slabs become seamless

Double stone slabs act the wrong way. Placing two stone slabs onto another yields a double stone slab with data value 8 (which is the same on all sides) instead of the correct double stone slab with different sides, at least in creative mode, and other type of slabs (sandstone and quartz, specifically) might be affected too.
In addition, I am unable to /give myself double stone slabs, which makes some types of them unobtainable even when intended to (double_stone_slab:8, double_stone_slab:9, double_stone_slab:15, and the wood-textured double stone slabs).