Somewhere between June 21 and July 25 something has caused the altitude to be incorrect on my Marq Athlete.
The first image is from June 21 .. As you can see it is pretty flat. And the same route on July 25 and suddenly I have a 40m descent or something. And as of that time my altitude is incorrect. Someone else experiencing this? I have done the altitude calibration but that doesn't seem to help.