Unrecognized property: duplicate_option/ Lead Source Id is invalid

I cannot create a contact without email duplication and with lead_source_id.

https://api.infusionsoft.com/crm/rest/v1/contacts/?access_token=___TOKEN___` resulted in a `400 Bad Request` response:
{"message":"Unrecognized property: duplicate_option"}

https://api.infusionsoft.com/crm/rest/v1/contacts/?access_token=___TOKEN___` resulted in a `400 Bad Request` response:
{"message":"Lead Source Id is invalid"}

Before setting lead_source_id I check it and it is a valid contact_id.

If I use XML_RPC, the LeadSourceId is not saved.

LeadSourceIds are not ContactIds. They are identifiers for acquisition channels. We don’t currently have a REST endpoint to retrieve them, but they are available on the Legacy XML-RPC API via DataService.query on the LeadSource table.