Advanced Cauldron doesn't run with a single chest.

When the advanced cauldron only has a single chest, it'll refuse to run because there's not enough space. 
Adding a double chest fixes this, but there should be enough space left for the XP.

Steps to reproduce:
Make a Advanced Cauldron with 1 chest.
Try to run a recipe.

Only tried this with recipe 2 so far, and the factory facing east-west. 