The sync between EngagementHQ and Campaign Monitor brings across ALL participants, regardless if they are activated or not, imported or not or even blocked.
If you see a difference in numbers, consider this:
Your EngagementHQ Participant List includes Project Administrators. They are NEVER synced.
Your CM account has a suppression list that includes email address of people who have previously unsubscribed from your emails. We are NOT syncing those emails from EngagementHQ to CM.
The lists are not updated in real time, but only when a sync occurs. Depending on when you check, the most recent registered participants in your EngagementHQ might not be synced yet.
Note : The auto sync happens at 4am AEST.
To check your suppression list, see this help article from Campaign Monitor
Contact our support team if you need any further assistance via chat or email email@example.com