Things we have tried:
emptied farms and the warehouse then started farms with coal in fuel slots then started ware house
put all the fuel types in inventory of warehouse and farms
start warehouse collecting first then turn on farms
put each type of fuel in fuel box
destroy warehouse and replace new warehouse
Turn farms and warehouse on and off several times
placed stacks of each kind of wood normally gathered along with thatch in ware house
Things we are gonna try:
Turn off ware house and let farms fill with resources before turning warehouse on
replace farms with new ones