Bug with the beacon's diamond texture

What I expected to happen was nothing special
I don't trougth something special happened

What actually happened was the disparition of a side of the diamond block inside the beacon when placing a block next to it
When placing a block next to a beacon, the side of the diamond block next to the block dissapears.

Steps to Reproduce:
1. Place a beacon anywhere, it works in every situation(just make sure there is no block on the sides of the beacon)
2. Place any bloc next to the beacon
3. The side of the diamond will disapear