Describe the bug
When exploring the overworld, you may come across a barn house that seems normal at first glance, but has some incorrect block values.

To Reproduce
Steps to reproduce the behavior:

1. Explore until you find the barn house structure shown in the screenshot below (minus the windmill and chests).
2. Attempt to mine the top two layers of blocks on the roof with an axe.
3. HWYLA will show the vanilla wooden slab blocks to be breakable with a pickaxe instead of an axe.
4. After breaking the wooden slabs at the very top with a pickaxe, they will drop as missing texture vanilla stone slabs.

Expected behavior
It is to be expected that wooden slabs would drop as themselves and not have stone stab values when placed.

Screenshots
[Structure]:

[Item data in question]:

Info (please complete the following information):

• Modpack Version: 2.77.5
• Server or Singleplayer: Server
• Version the world was created on: 2.77.5

Additional context
The only structure tested with this bug has been the one in the screenshot.

I'll look into it

Fixed by f8d0142