If a lead or contact is deleted in Salesforce, the integration will not delete the contact in ActiveCampaign.
If the contact or lead you deleted in Salesforce is updated/edited in ActiveCampaign, then a sync will be triggered and the contact or lead will be added back to your Saleforce account. To prevent this from happening, you will need to remove either of these tags from the contact record in ActiveCampaign:
- added-to-salesforce-contact
- added-to-salesforce-lead
Once these tags are removed from the contact record in ActiveCampaign, the sync will not run.