I can't get mason brinks because the granite or ironclad anvil won't let me place stone bricks on them. The manual and JEI say I have to put stone bricks on one of those anvils and use a flint or above pickaxe to get a stone brick slab. Then do the same thing with the slab to get the bricks. But neither of the anvils will let me place a block of stone bricks on either of them.

I'm playing on a modpack I'm developing. Do you have any idea what could possibly be conflicting with this?. The only thing that I could think is Better with mods. But I'm not sure if it has any changes that involve stone brick.

Are you playing a modpack or have you otherwise altered the recipes?

I'm unable to reproduce this.

Do you have any idea what could possibly be conflicting with this?

I have no idea. You could try disabling mods one at a time or in groups until the problem goes away.

@TheSexyYeti Were you able to solve this?