I sincerely apologize for the inconvenience; I have looked into this and found out the problem was caused in the newer version of Minecraft which made the transparent cube gone corrupted. We have deployed the fix on the newest version of the product [version 1.2]. Please download it, and replace the ModelEngine file and run the command /meg reload ,followed by reloading your resource pack plugin, and the problem shown in the attached link should be fixed! Again, we are deeply apologetic for this, we will continue on delivering our client the highest quality product.