The Production tab on the Statistics view seems to get confused if I go and change the crops on the hacienda farms. Here is a screenshot where I changed some farms and removed all the sugar cane production. However, it still shows it being produced by a spice farm and a corn farm (and they do correctly produce spices and corn).
The graph view seems to calculate the sugar cane production correctly, as it - I believe - just counts the actual number of tons produced, while the supply bar just shows the production speed in factories.
The multifactories don't seem to suffer from this bugs; only the hacienda farms.
This bug also seems to correct itself from saving and reloading, luckily.