If an Induction Furnace smelts an odd number of items that isn't the first in a batch, it will produce an extra item on the last smelt

@abculatter2 could you provide a video example Because if this was a thing then i would have gotten that report months/a year ago.

I'm not able to record video, unfortunately. I did download the latest 1.12 version from a few days ago on Curseforge, so it should be latest or close to it.
I didn't test it extensively, but literally all I had to do to replicate it was place an odd numbered stack of items 3 or above into the furnace and let it run until it finished the stack. It then produces an extra item on the final operation.
I can do some more testing tomorrow, if you'd like, and also take pictures of the set-up.

Yeah found the issue. Thats patched now.