Something similar happened to me but it happened when I relogged (save and quit to title). When I opened my world, all the items in the furnace I was using were deleted (fuel, input, and output) and the furnace still had the smelting texture. I tried doing it a few times and sometimes the items wouldn't be deleted if I took one of the outputs out of the furnace.
EDIT: seems to only happen when Winter Drop is enabled
ryekew
Something similar happened to me but it happened when I relogged (save and quit to title). When I opened my world, all the items in the furnace I was using were deleted (fuel, input, and output) and the furnace still had the smelting texture. I tried doing it a few times and sometimes the items wouldn't be deleted if I took one of the outputs out of the furnace.
EDIT: seems to only happen when Winter Drop is enabled