Kingdom power is increased by 1 when reaching kingdom level 10. It is supposed to increase again at kingdom power level 5.
Most of my kingdoms are power 6 or above and they all show power level +2 as they should. I have 2 kingdoms - Bright Forest and Dhrah-Zum that are Power level 5. They should be + 2 according to the power level charts, but the power level within the kingdom is only +1.
Platform is iOS. Version is 220.127.116.11
Have confirmed with others they see the same thing. Screenshot attached.