Minecraft 1.11.2, Minecraft 1.12 Pre-Release 5
When placing a shulker box, if you are too close to it, it will vanish until you go into your inventory and click on its hotbar slot, or if you reload the world.
What I expected to happen was the box to place.
What actually happened was it appeared then vanished. see the included GIF.
Steps to Reproduce:
1. give yourself a shulker box and a pickaxe.
2. Go into survival mode.
3. look at the floor and position yourself at the corner of the block you want to place the box on.
4. Place the box. If the glitch doesn't occur, break the box and move slightly forward or backwards.
5. Once the glitch occurs, go into your inventory and click on the hotbar slot the box was in. it will reappear.