This method you have is only for in-world rendering.
https://github.com/xbony2/AFSU/blob/master/src/main/java/xbony2/afsu/blocks/AFSUBlock.java#L58

This method however, is used for world, inventory rendering.
https://bitbucket.org/master801/801-core/src/269f5f517579fabf2f46f20928a905028d2e6cd4/core/block/BlockCoreBase.java?at=1.7.10#cl-279

I would make a pull request myself to fix this problem, however I'm rather lazy, and would rather for you to fix it yourself, instead of me.

You can thank me later.

So THAT's what the difference between those two methods are! Thanks! :P I couldn't figure out why my null checks and stuff weren't working.

@xbony2 Lol