During my first ever game of CBE, I ended up with about 8 worker units. Not wanting to micromanage them, I set them all to auto. They automatically built mines/quarries on strategic resources, and also built roads/magrails between my cities. Once that was done, they all gathered around my capital and proceeded to build farms in place of whatever improvements were already there. As soon as they finished building a farm, they immediately started building generators on the exact same tiles, wiping out the farm they had just finished. Once those generators were finished, they immediately starting building farms again, on the same tiles.