Marketo or SFDC is unsubscribing leads via list imports / web api

[Anonymous]

We have integration with Integrate - we get new leads from web APIs and we also import lists into Marketo programs. 

Recently, I've noticed that our leads are automatically being set to unsubscribe without any triggers or information of where it's coming from. 

Some (rather most) of the leads imported via list were existing in Marketo already. When they were imported, all these flows happened and all were set to unsubscribe=true. We looked on the SFDC record and in the history it says Marketo Sync is changing the unsubscribe, but in the Marketo record, it says the sync is coming from SFDC. 

Has anyone ever experienced something like this before? 

Any help would be appreciated!

[Kenny_Elkington]

Hi Jackie,

This is what's called 'Durable Unsubscribe'  If a lead in your instance has unsubscribed set to true, any other records which are added to your instance with the same email will have this set to true as well.  This will also persist across deletions.  You can read more about it here: https://community.marketo.com/MarketoResource?id=kA650000000GxXxCAK