My BCD536HP is installed in my truck for mobile operation, and the 12 volt power supply wires are connected directly to the battery ( fused). I recently noticed that if the radio is in use / scanning with the engine off it will restart / reboot once I start the engine causing anything I was monitoring to be monetarily lost until the radio restarts. I understand that the high current draw of the engine starter causes a momentary voltage drop, but doesn't the radio have an internal battery to avoid this situation? Is what I'm experiencing normal?