Even if you put 5 raw pork into it, you will only get one cooked pork. Besides, when right-side bar is full, you'll get nothing and pork disappears.

What do you mean by the beehive kiln? A forge? A fire pit? A pit kiln?
Please explain exactly what you are doing, in specific detail, and what is happening.

Sorry for that, I think it should be Forge, that's my fault and I have changed the title.
I recorded a gif to explain this.

This also happens in fire pit.

Is "cateoryMeat" a typo?

I think it should be categoryMeat, but sadly it's hardcoded. There are too many things hardcoded.

Yes it is a typo. But it's a bloody ore dict value. It's literally the easiest thing to tweak if you are so inclined. The meat cooking is very much a bug.