Able to place block inside of player

I right clicked on a sign that was placed onto the side of a chest, with a block in hand. I was expecting to open the chest. What happened was the block was placed 'on' the sign, and inside of the player, causing it to begin to suffocate.

Steps to reproduce:

• Place sign on side of chest
• Carry a block in hand
• attempt to place block on sign, while standing next to chest