"Marketo associates Opportunities and contacts using Opportunity Contact Roles. Opportunities without any Contact Roles assigned will sync to Marketo, but won't belong to anyone. For example, the person won't qualify the Has Opportunity filter."
If the Contact in Salesforce has an Opportunity Contact Role, reach out to Marketo Support to check if there is a sync backlog.
Who This Solution Applies To
Customers who has Salesforce integrated to Marketo