There are a lot of things stored in NV memory, and some of them are not even that visible.
For example, even if I reset my average consumption, the range is still calculated on the previous values and updates as I drive onward as if I've never reset the average (I guess it must keep a separate average for the last 5-10 km or so).
My average MPG display seems to randomly reset at startup. Most of the time it only resets when I refill the tank. But over the last couple of months, it seems to be randomly resetting at startup, maybe once every 3 or 4 starts. I've owned my 2017 for more than a year now and it never did that in the first 8-10 months. Anyone else seeing random reset behavior of the average MPG display?