As a quick attempt you could try and reload the same firmware, or a newer one, i have 1 time tried a dashcam that somehow backed itself into a corner and had some kind of error ( i can not recall )
But anyway loading the same firmware again fixed the problem, and it never came back as i flashed the camera several times more with newer firmwares in the months that followed.
I can not remember what kind of error the camera had, but i can for sure remember that it was using a regular power supply as back then i was not given the equipment to test parking guard.
Its worth a try i think as its pretty fast and no tools required, just need to do settings after the flash and the subsequent reset to default settings.
Also you might want to try the camera for a day or two just using the regular power supply from the kit, just to make sure its not the camera itself.
Also X2 if you have a rear camera on there, you might want to try disconnecting it and see how the camera boot then while using the different options for power, a flaky rear camera wire have been known to result in inconsistent behavior.