For anyone who might have a similar issue in the future, I found that there is NO overvoltage protection on the power management unit, the AS3713PMU. Any overvoltage will likely result in the Power Mangement Unit to fail, which can be indicated by a massive power drain and heat signature of the PMU. (I verified this with a thermal imaging camera) Unfortunately, I was unable to source another AS3713PMU, so the camera was cannibalized for spare parts, namely the lens components.
If anyone hopes to power the camera from an alternate external power source, do keep it less than 5 volts!