Redstone not wiring vertically

While placing redstone dust on slabs vertically, the slabs appear to be connected as they usually would with vertical slabs. Though, when you power the redstone, it appears that any redstone on a lower-leveled slab doesn't turn on/get powered. Its very weird because the redstone DOES seem to, in fact, power other redstone on a higher-leveled slab. Also, it unfortunately doesn't even power the redstone that doesn't connect. Please fix this bug as it makes some of my machines useless and also makes some redstone contraptions hard to make.