CubeOrange+ outputs 35v to the buzzer?

Hi users,

I was using cube orange+ for one of our drone(450mm frame - Quadcopter), I had noticed an unusual thing. I had measured the voltage of usb port where we connect buzzer , it was showing 35v in multimeter. I was using 4S LiPo battery with one power module.I had taken one flight in altitude hold mode for this frame for around 2 mins before noticing this issue. But in mission planner I had not seen any warnings regarding this.

Is it safe to take another flight with this flight controller ? Please suggest me to resolve the issue.
Below I have attached two photos showing nearly 33V in multimeter. Here I had only given power to flight controller through the USB of the computer.

Situation normal.
The Cube has a built in step-up convertor for supplying the buzzer positive, and the other pin is pulled low to make noise.