I've seen a few posts on this and made some myself, but I now have conclusive evidence that Garmin have broken climbpro in the transfer of routes from Strava (and maybe other platforms) to Garmin Connect.
The problem is that Garmin recalculates the elevation data, but makes a mess of it. The image below is the elevation of the same route (via GPSVisualizer), one trace is from Strava, and one is from Garmin Connect after transferring it through the API (favourite the route in Strava and it comes through automatically).
Heres the Garmin vs Strava elevation at the start of the route
and here it is at the end
Heres the full trace, at the start of the elevation profile its fine, at the end its way out.
