This mechanism is called the hysteresis cycle. Now imagine you reach the low water mark at 1.5 km from your destination. After for example half that distance you may have recharged enough power to reach your destination in EV mode before hitting the low water mark again. But, not knowing what your destination is, the car insists on completing the hysteresis cycle until the high water mark is reached. Consequently, you are generating power that you do not need in order to get to your destination.
Stopping or slowing down the car may change the cars mind on completing the hysteresis cycle. Sometimes, it seems slowing down to almost 0 MPH is sufficient, sometimes I really need to make a full stop to brake the cycle.