The bottom fans are requiring more energy than they are producing (because they are shaded) , so the plant is self-pruning in order to put the energy into flowering. I don't see a problem... it's what they do.
Plants are essentially solar powered factories. The plant manager has to pull workers off the production lines in order to do routine maintenance on the panels. If a panel is always in shade, this leads to a net loss of productivity because they lose production in order to maintain something that has no positive benefit to the company. The obvious solution is to remove the unproductive panels and let the worker stay on the production line.