Issue:
In the recent 1.6 update you could customize the "follow range" of a mob, such as the zombie. With the new feature I wanted to create a mini game where the player would try to find the exit to a maze, while a zombie could track down the player with its increased follow range. I decided to create the maze out of the leaf or leaves block. I choose this block because I saw a video recently where a zombie could track a villager through a maze of leaves and find it with no problem. Here is the link to the video:

http://www.youtube.com/watch?v=MyFIxvK-sxs&feature=c4-overview&list=UU8aG3LDTDwNR1UQhSn9uVrw

So I then created the entire maze out of leaves, very similar in the video. Then using a program know as "MCedit" I was able to increase the zombies follow range to about 100. Then I put the zombie at one point of the maze and a villager at the other. As expected the zombie was able to track down the villager. So thinking: "if this works for villagers, then it must work for players also". So then I placed myself down in the maze, about 10 to 20 blocks away from the zombies current location. I was expecting for the zombie to come and find me, but it didn't. I was at first confused because it worked for the villager, so I thought: "Ok, maybe I am in a location where the zombie couldn't get to". I then moved myself to another location in the maze where I knew the zombie could get to, and it still couldn't find me. So as a test a placed a villager next to me, and sure enough the zombie was able to locate the villager, but not me. I believe what is happening is that because zombies are programed to find villagers not matter what, they can find a villager in a maze very easily. Plus, mobs are able to locate players through leaves, so this makes finding the villager even easier. The zombie, when looking for a player, treats the leaves like another block such as stone or some other solid block. But when looking for villagers it treats leaves just like leaves or as a non solid block. And yes, I was in survival so that way the zombie could track me.

How to recreate:
1. Create simple maze
2. Spawn Zombie and edit follow range
3. Spawn villager and watch the zombie find the villager
4. Place yourself in the maze somewhere you know the zombie can get to
5. Wait for zombie to find you
6. Discover issue

Thank you for your time.