Club activities don't include activity timestamps when returned from Strava. So the first time we get a bunch of old activities, mark them as "first sync" and don't publish them. That's how Slava knows that anything since then is new and thus needs to be posted. But since https://github.com/dblock/slack-strava/commit/ebfb98bbcd4d0baafcb9918b5190e1c93cb70409 activities are only stored for 30 days, so older club activities get deleted and re-fetched.
Club activities don't include activity timestamps when returned from Strava. So the first time we get a bunch of old activities, mark them as "first sync" and don't publish them. That's how Slava knows that anything since then is new and thus needs to be posted. But since https://github.com/dblock/slack-strava/commit/ebfb98bbcd4d0baafcb9918b5190e1c93cb70409 activities are only stored for 30 days, so older club activities get deleted and re-fetched.