Weird Block Rating bug?

Hi, so I just got a new shield on my prot pally on Icecrown, and I immediately noticed something weird when I put it on. My block percentage was a bit lower, despite being a far better shield. My block rating went from 13.34% to 11.44%... and I thought that was really weird.

It got even weirder when I scrolled over my Block Chance, and noticed it said: Block Rating of 0 adds 0.00% Block". So, my shield doesn't seem to be giving any block rating? I don't know if this is a visual glitch or not?

Here is a visual example: https://i.gyazo.com/b7e7f32672252afc...6865270e6c.png
The shield in question is Icecrown Glacial Wall (Normal Version), my old shield was Bulwark of Algalon... I was so happy I got my shield, I sold my Bulwark of Algalon... but now it seems like my new shield doesn't seem to be working.

What's up with this? Is it a visual bug? Should I be legitimately concerned?

Greetings

Block value=/= Block rating. Block value decreases dmg and doesn't increase your block rating.

http://wotlk.cavernoftime.com/item=50729

And for the next time, show shield enabled and disabled, and the tooltip of the shield instead of a extremly sliced pic. Ppl don't help you otherwise, when they have to "google" everything

Regards