When standing inside of a banner, transparent blocks can be seen

When standing inside a dyed or undyed banner, any block or fluid that is some level of transparent can be seen through the banner.

What I expected to happen was...:
I should have only seen the inside texture of the banner.

What actually happened was...:
All transparent blocks were also visible.

Steps to Reproduce:
1. Place any banner
2. Stand inside of the banner
3. Look at a transparent block or water