Furnace Makes A "Clicking" Sound When In Use

I don't know how to describe it other than clicking. Its kinda weird.

I went through a second time without music (when I tried recording it), and I think the best way to put it, is that it sounds like a mob (sheep, cow, pig, etc) walking, but the only mob there is, is my cat, and it's sitting.

I remember it happening one time when a drowned was nearby so I thought it might of been it somehow so I waited till I got more info on what was going on. This time the only mob I had around (that I knew of) was a tamed cat.

This only happens when the furnace is in-use, and it seems to make this noise at the tick speed. I normally only use coal unless I'm getting rid of wood junk, so I don't know how it reacts to other burnable items, if that may affect it. When the flames that show how much fuel is left goes down one, it "clicks", and when whatever it is I'm cooking/smelting finishes one item.

I made a video, but it says the file is too big... (35.04 MB)
In the video, it didn't seem to line up, and maybe the furnace is supposed to make noise and I'm just stupid. But if this is abnormal, I would enjoy the fix, because it is annoying and gets on my nerves a little bit..