As others have noted, the ETA is often wildly innaccurate, with many users reporting the ETA is just a few minutes to go. Well I think this happens during a ClimbPro climb. I think there's a bug (please tell me this is a bug and not a feature!!) where the ETA field is inadvertently being reused to display the ETA to the end of the climb. I expect someone's reused the field by mistake within a Climb Pro algorithm. Anyway, after the climb, the ETA field reverts to a sensible value. Flipping annoying anyway, hope it gets fixed.