Unexplainable increase in efficiency

🚧 THIS IS A TICKET MIGRATED FROM UPVOTY. The original ticket and comments will be available for a limited time over at:
https://abrp.upvoty.com/b/report-a-bug/unexplainable-increase-in-efficiency/
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I don't use ODB but rather have been able to calibrate the base efficiency for my car (Kia e-niro 19-22 64kwh) over many trips, recalculating after the trip so that estimated battery matches actual. It's been working for about a year, but at some point in the last few months i had to make the adjustment from around 140 Wh/km @ 110km/h to 95 Wh/km! It now works accurately for trips but it seems like a bug. I've checked all of the relevant settings i think, logged out then back in, etc but this is still the case as of today.

Mostly I'm worried that I'm not going to be paying attention and one day for a longer trip the calculation goes back to "normal" and I'm forced to stop for an unplanned charge.