When this happens to me I'm going from a higher to a lower elevation. I drove 19 miles yesterday across Tucson and ended my drive with a higher % charge than when I started.
A guess - could this be at least in part the car having trouble monitoring the current state of charge of the battery? This is an LFP battery, right? LFP batteries are harder to monitor state of charge since their voltage doesn't drop like NCM. That's why the Ford manual recommends we "charge to 100% at least once per month to maintain range accuracy". Perhaps your car struggled to know how much was actually in the battery?