Minecraft 1.8.8, Minecraft 15w34d, Minecraft 15w44b, Minecraft 15w46a, Minecraft 15w47a, Minecraft 15w47c, Minecraft 15w49a, Minecraft 15w49b, Minecraft 15w50a, Minecraft 15w51b, Minecraft 16w06a, Minecraft 1.9 Pre-Release 1, Minecraft 1.10.2, Minecraft 16w41a, Minecraft 16w42a, Minecraft 16w43a, Minecraft 1.11.2, Minecraft 17w14a, Minecraft 17w16b
Trying to replace a replaceable block, such as Tall Grass, Ferns, a Snow layer, Vines etc, with specific blocks isn't possible, if you try placing one of those blocks on the side of the block you want to replace.
Only attempting to place at sides of replaceable blocks makes this happen.
The "specific blocks" are Banners, Signs, Doors, Beds, Levers1, Buttons1 and Double Plants2
1 Bug reproduction only when no other same-height blocks are next to the replaceable block.
2 Bug reproduction only when trying to place at side-hitbox of Double Tallgrass and Large Fern blocks.
Note: In version 1.8.8, you can't replace replaceable blocks with the specific blocks by placing them on the hitbox-top of the replaceable blocks. This isn't the case with 15w46a and all other tested snapshots. The fix of
MC-64139 may have made it this way.
https://youtu.be/Sh9r_fb6GN0 (Uploaded by Crazy_Matt)
Original reporter: Crazy_Matt