This is a known error and started sometime between 3 and 5 Feb probably during the GC maintenance shutdown. I have an Edge 510 with exactly the same issue.
However: I reckon it might be a button display issue. Make a note of your elevation gain, click Disabled and see if the gain changes. I reckon that mine actually defaults to Disabled even though it says Enabled, based on the shape of my regular commute (the local survey data are incorrect on part of a climb).
When I repeatedly click Disabled it toggles between Enabled and Disabled.