[?] Zombie Survival: CPE block bug.

[Leeizazombie]

I was playing on Zombie Survival, and I camped in a place where there was fire blocks (CPE's Fire) and it show's the message to OP's that I'm walking through blocks.

[dzienny]

Can you reproduce this problem?

[Leeizazombie]

Here's a screenshot of what I was trying to explain. I hope this is a clear sight:

http://puu.sh/8hURO.JPG

I believe it's acting like a normal solid block.
But it takes like 3 - 5 seconds of standing in the block until that message shows up.
I found this out on another server, so I tested on my local server and it still happens.