When the battery module charge is at or above a specific value
WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. However, it is still accessible from the selected car via links, so may be relevant.
When the SOC of the battery module is at or above a specific value, the generation amount is restricted to prevent overcharging. Since regenerative braking force is insufficient at this time, the PCM cancels full cylinder deactivation and increases engine braking power.