Saturday I helped someone get a PR on their half, I had her doing a decreasing run walk cycle on a almost pancake flat course, maybe 150' of vertical over the full 13.1 miles.
But I ended up with almost 2000' of vertical on my 6X. She ended up with 160' with a 965. Every run section, without fail, the elevation started climbing and when we stopped running it went back down. Every time and it was a lot of run/walk cycles, we did 16 repeats each of 3:3, 2:2, 1:1. And each cycle, the same thing. At the start of the run, elevation would go up then come back down in the walk.
To be clear not really looking for answers and I'm not freaking out about it, I just found it very interesting, I've had my 6X since a week after release, have run every day for over the last 3 years have put multiple ultras and about 4000 miles on this watch and haven't ever seen this before and thought it was weird enough to share in case someone else runs into it.
Battery's getting a little long in the tooth now but it still gives me about 7-10 days between charges with the daily runs.