Not to doubt your bug’s existence, but if you get this happening again, can you double check that they aren’t being placed on the blacksmith’s anvil? I think that would remove them from the inventory. If there aren’t 4 ores, then the blacksmith won’t make an ingot and the ores will sit there untouched. Anything else in queue won’t be worked on.
If you cancel the order, do any of the remaining ores disappear or are they all placed back in the stockpile?
Lastly, what version are you running? Are you playing the regular steam one or the latest-build? Any mods installed?
Thanks for the report!