The Zwift activity grouping feature has been disabled for the time being. Grouping Zwift activities pose a unique scaling issue which unfortunately has caused major delays in grouping for all other activities on Strava. Due to this situation, you may see Zwift Runs on Flyby for your ride. This is also an issue we are working to address. We appreciate your patience while we investigate possible solutions.
Update: We are bringing Zwift group activities back, so you may now see your activities grouped as expected on Strava. Stay tuned for more updates on Zwift activity grouping and Zwift Flyby.