I remember reading this somewhere but correct me if I'm wrong: The marketo API will pull newly created/updated records from Salesforce into Marketo PRIOR to Marketo data being pushed into Salesforce correct?
Recently, the team cleansed a large subset of leads from Marketo, but it looks like the leads may have been repopulated into the Marketo database because the Salesforce to Marketo sync occurs first. Anyone have insight into this?
Next time, better enter a question than a discussion, you will be more likely to get answers
It's not about the fact that the sync occurs in this order, it's because Marketo presumes that SFDC is right unless you explicitly say so.
When you delete persons from Marketo, you have the option to also delete them from SFDC. 2 things may happen that could explain what happened to you :
If you need to have significant volumes of persons that exist in SFDC but not in Marketo (for instance to manage inactive contacts), you probably need to set up a sync filter. You will find some readings here: