In that case you aren't getting water back into the brine tank as you should. The cause would be a blocked injector screen or injector or the internal port between the screen and injector. The ball will only float IF there was water going to the brine tank as part of Refill, which happens during the settle rinse.
Overfilling the brine tank means no or incomplete suction (Brine Draw) leaving more water in the salt tank than should be, and incomplete regeneration, and that is caused by a suction air leak during Brining and then Refill putting back the water that was supposed to be sucked out, overfilling the salt tank. Causes are air leaks in the brine line fittings, blocked injector and or screen. Kinked/blocked drain line or low water pressure.