You can place shulkers and shulker boxes in the space as a player

Steps to reproduce:

1. Look down

2. Place a Shulker / Shulker Box

3. The shulker will be placed in the same space as your feet and you will be teleported to the side

if you watch a video, you can see when i placed a shulker block on my foot (without jump), it auto move player by itself. (Easy, when you place a shulker block on your standing block (player foot) and then you place without jump, it auto move player when placed)

Better title/steps from @unknown