Calendar Activity Mapping is only available on the new candidate profile. Everything below assumes the activity was attached from there. See What's Changing: The New Candidate Profile if you're not sure which layout your account is on.
When you attach a custom activity to a calendar event, Recruiterflow keeps the two linked, but the sync only runs in one direction. Here's exactly what updates automatically and what doesn't.
The activity is logged on the event date
When you save the event, the custom activity is created with the same date as the event, not the date you happened to be scheduling it.
Editing the event updates the activity's date
If you change the event's date or time, whether from Recruiterflow or from your connected calendar app, the linked activity's date updates to match.
Editing the activity does not move the event
The sync only runs event → activity. If you change the date on the custom activity itself, the calendar event stays where it is. This is a one-way relationship by design.
Deleting the event deletes the activity
If you delete the event from the calendar, the linked custom activity is removed too. Deleting the activity on its own does not delete the event.
Who gets attributed
The custom activity is attributed to whoever scheduled the event, and it's associated with the same candidate the event was scheduled against.