The bug
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.
Video
https://youtu.be/Sh9r_fb6GN0 (Uploaded by @unknown)
Original reporter: @unknown
Linked issues
Comments 4
@@unknown: Ticket is yours, please update it yourself.
With snow layer >1 it is posibly intended
Can no longer reproduce in 17w48a.
migrated
Confirmed for 15w46a.
This issue should be updated.
Signs are also affected. Placing banners on a snow layer is fixed (see MC-64139). Placing banners and signs on ferns and large ferns, double tallgrass and dead bushes isn't possible.
Relates to MC-64139.