We have successfully synced a LinkedIn Lead Gen form to our Marketo instance. However, the Lead Source field appears to be overwritten. In the LinkedIn Form, there is a hidden field for Lead Source with value of "Social". When the test lead was created in Marketo, the Lead Source was "LinkedIn Lead Gen". This is not a picklist value in Salesforce and will cause issues downstream. Any ideas on how to force the "Social" Lead Source value? Screenshots below.
Form mapping in LinkedIn Lead Gen Form
Mapping in Marketo Admin
Activity Log Detail when test lead is created. Note Person Source is not "Social"
Rather than having the Lead Source value sync down from LinkedIn, can you have an Operational program that listens for new records created by LinkedIn Lead Gen and set the Lead Source using a flow step?