Viofo confirmed that the camera saves the settings every time it shuts down, which doesn't make any sense.
It does sound a bit redundant indeed, but there's no harm in doing this. If the cam is used (read: turns on and off) say 10 times a day (which is usually hardly a case I guess) the number of such EEPROM writes would be 4000 per year. Modern EEPROMs have 100K write cycle limits, which means 25 years of eeprom life in those conditions. No worries.
I understand that the problem may be a power glitch during an EEPROM access, and that's what was meant to be taken care of by using those two big internal super-caps, which apparently are not doing their job properly in your case. Read also below.
I haven't read the full thread, but, can you confirm that the dashcam is in regular use, say at least an hour a week, which should keep all the internal capacitors and the RTC battery charged ?
If so then my incling is a defective capacitor
That's "inkling", I guess...
Funny that - I disagree with your reasoning (above the empty line in the quote) but fully agree with your conclusion, below that line.
Firstly, RTC battery is not meant to be charged at all. It is a litium (not LiIon!) coincell non-rechargeable battery, and when it is fully exhausted, it just needs to be replaced, not charged.
The fact that it gets "charged" every usage of your dashcam, so you get some more life out of it after that, indicates (to me) a hardware design flaw on viofo's side, because charging those batteries damages their internal chemistry.
Secondly, the supercaps inside the cam, when fully charged, can normally maintain the internal power rails only for a few seconds after external power goes off.
This is just to give a processor enough time to properly complete writing of the current video clip and finish other home duties before everything "dies".
If saving settings to EEPROM is a part of those "home duties" (as the above-quoted post of
echo_ suggests) then the compromised time of "life support" provided by the (inferior) supercaps, can indeed lead to the incomplete/corrupted record of settings, which will be then reset to defaults due to a checksum failure, on the next power-up.
Just one of the many possible scenarios.