I created a custom formula field in salesforce that captures the lead owner if the lead owner is a queue. I could see there are around 47k leads currently in marketing queue in SFDC whereas in marketo it shows only 1300 leads.
This looks more of a sync issue. Could you please let us know the sync interval between salesforce and marketo for the existing leads. Also is there any criteria/rule that triggers the sync between 2 systems. Yesterday we manually pushed the sync then the lead count in marketing queue raised to 47k. This is a serious problem for us.