I activated a Harvest Champion boost when harvesting the Sweet Flower Buds (Sweet Honey Flowers) but it does not double the harvested quantities. And no energy is returned regardless of the number of Sweet Flower Buds harvested.
I tested it on a corn crop as well and the Harvest Champion boost does not work either.
Please turn the boost and energy return on.
Sorry, just realized that I had 98 pieces of corn in storage, so it was correct that the single plot of corn yielded only one corn. I used up some corn and harvested more corn and the boost is good. So it only needs to be switched on for the Sweet Honey Flowers.