Badger6

Interesting, and I stand corrected. I found an official Strava reply in their support pages, after reading your reply, where they express that they import the calorie calculation from a .fit or .tcx file if that is how your linked device saves the activity. Now that you've mentioned this, I realized that the calories in Strava have been exactly matching Garmin for some time now. Thanks for the digging, I assumed that the Strava counts were still being calculated by Strava.

But, that said, I've not been alarmed by them as they seem to continue to match the rule of thumb for work to calorie correlation of nearly 1:1, meaning the power data to derive total work (kJ) correlates almost 1:1 for calories has continued with no issues, I guess because Garmin hasn't messed this up.

With respect to relative effort, that is based on HR data. The abnormally low (I assume) HR on the linked ride is what that number is so low when it would appear it should be higher...but remember, the relative effort is relative to you. So if your HR zones are set incorrectly, it will give reading that don't seem to match the RPE.