Update, I think the cause is removing items from the workstation such as taking shaped wood out of the carpenter’s bench or when a piece of wood is burned in the stove. Basically, it seems to be correlated with removing items from the station’s inventory.
I can confirm on the carpenters bench (Improved) that when making shaped wood and insulated wood. If you take out all the shaped wood that has been made and let the que run it will clear it. You have to rerun the craft all. I have not had this happen on any other bench, just the carpenters.