My Garmin Edge 520 Plus that was loaded with software version 5.70 recording elevation at roughly 75-80% of what it should have been. I would say that it was tied to a software installation but I had installed 5.60 on April 2021 and noticed the elevation started calculating differently a month later. I had 5.50 loaded prior to April 2021 and had no issues.
However, one of the buttons wore out on my device and I had to exchange for a refurbished Edge 520 Plus loaded with software version 5.50. The elevation is recording as normal and my elevation calculations are correct.
Does anyone have an explanation for the elevation discrepancy? I am at the point I don't want to upgrade beyond 5.50 just so my elevation accuracy remains in tact.