I've connected my accounts (validated in the settings in both accounts) and yet the activity I posted since connecting them has not synced from Garmin Connect to Strava. I also tried disconnecting and reconnecting the accounts to see if that was the issue, even deleting the activity and reposting after reconnecting the accounts. Still hasn't posted to my Strava.
The reason why I'd like to post to Strava this way, aside from the convenience, is that Strava always under-reports my power data when compared to that shown on my Garmin Edge 500 and the activity on Garmin Connect.