I have created a new Journey in Marketing Cloud for new Salesforce Lead records (using Salesforce Data) as the entry point.
The purpose of the Journey is to send information to the Lead until they become a Converted Contact. I have noticed however once the Lead is converted there is no Contact data associated to this person, even the original Lead record.
I have done some research and it appears the Lead_Salesforce object that is synced, uses a surrogate
_ContactKey to associate records together, when the Lead is converted, this changes from the Lead ID to the converted Contact ID. So when I try to look up Contact data (through a Decision split or Goals) it cannot find anything as the original key is still the Lead ID, but the synced record foreign key is now the Contact ID instead of the Lead ID.
I know Leads are not recommended to be used in Marketing Cloud, but this is how the implementation has been completed and there is way more rework to switch to Contact (and record types). The previous admin claims that this solution worked before, and no changes have been done to the Data Designer/Model.
Can anyone suggest why the data isn't available and how I can retrieve the synced (live) data from my synced data extensions on converted Leads?