I think I discovered something.... big.

Mekanism machines are rotating 90° the top textures of nearby blocks, sometimes of whole chunk, whose top faces are at the same y-coord.

I was walking around in my base, then I found this:

Some cobblestone and grass blocks were rotated, you could tell it by the chunk border. I'm using Aeon resource pack (no MCPatcher or Optifine) since its cobblestone texture has straight lines for better visualization.

Now look at the following screenshots taken with the chunk boarder highlighted:

Those machines which are full and opaque blocks (e.g. Purification chamber, Crusher, Chemical injection chamber) rotate the top faces of any other blocks like furnaces, cobblestone, grass block, planks etc.

This is definitely still happening in build 8.1.2.229. Kinda problematic, aesthetically speaking, when building a base. Is this only fixed in dev?

Still buggy!!!!!!!!!

You really should ref issues in commits...makes it very hard to track this stuff down. This is a pretty serious bug, for the sake of your issue tracker I'd recommend releasing ASAP...

I was only able to track it down because I gave you the code to rotate textures in the first place >_>

Maybe something to do with the new renderer. Let me check...

Should be fixed