Coal should smelt 8 items; instead, it smelts like sticks. Sticks smelt the corresponding amount just the coal is affected. The bug only affects worlds with Experimental Mode disabled. My Survival Isle Challenge [β-Mt] has experiments enabled and is, unlike My Survival Isle Challenge [Beta] and Survival Only World, unaffected by this bug.
The video was Clipped and edited to be attached and for some understanding. The video has three parts; thus, I had to clip and move the clip to the start of the third part, which the clip contains the smoker on in My Survival Isle Challenge [Beta] world.