From the manual:
In the following situations, the parking brake
automatically operates.
• When the vehicle stops more than 10 minutes while ACC with LSF is activated.
• When the driver’s seat belt is unfastened while your vehicle is stopped automatically by ACC with LSF.
• When the power system is turned off while ACC with LSF is activated.
• When the vehicle stops with the automatic brake hold system activated for more than 10 minutes.
• When the driver’s seat belt is unfastened while your vehicle is stopped and brake hold is applied.
• When the power system is turned off while brake hold is applied.
• When there is a problem with the Brake Hold System.
If the parking brake cannot be released automatically, release it manually.
Also note it requires the 12 volt battery to be charged.