After further thought, I think placing the snow layer on the side IS a bug. Also, there was a block on the below where the snow layer should be placed.
I am unable to play minecraft right now, if someone is will to test this with slabs, that would be great.
-Thanks, Iam
I have had a similar problem, and I am unsure if it is the same problem. It was on 2.0.847, and the log can be found here: log. I am on Windows 10.
I think the reason of this is because the pistons don't get a block update. Not sure if this is a bug.
Want to suggest another place where terrain will spawn, in this case, the back yard of, I think the butcher. Grass spawns there, as well as in this case, a tree!
Not specifically the back of the house, they are both TaigaHills, but the center (well) of the village is Taiga.
I achieved this with a potion of harming II, and holding the totem of undying in my off hand.
Well, it appears that slabs DO work as intended.
Slabs can be placed on the side of a slab, and if placed on top, it will cause the block to turn into a stone double slab.
Additionally, if you use a non-snow-layer-item with the CanPlaceOn tag set to snow_layer, it also cannot be placed beside or on top of the layer.
I believe this has something to do with when you normally place a block on a snow_layer, it will take the block that you are trying to place and put it on the snow layer.
This theory is supported by the fact that tall_grass also has the exact same problem.
-Thanks, Iam