Deleted. See discussion here instead https://forums.garmin.com/apps-software/mobile-apps-web/f/garmin-connect-mobile-andriod/215573/bug-in-x-axis-spacing-of-all-activity-graphs-in-the-connect-app
The post is irrelevant here, since in Gamin Connect Web, the X-axis is linear. The issue you described here, concerns only Garmin Connect Mobile, hence it is off-topic here (besides being cross-posted). I commented on it in the original thread on the GCM forum, where it belongs: