Hi Marketo Nation,
We found that sometimes, certain fields are being overwritten with "[null]" at the exact same time. There are no Salesforce automations that would clear them. There is also no consistent timing for this to occur.
I created a Smart List and found a few patterns:
1. All affected records are overwritten via Sync by SFDC, either referencing a Lead ID or Contact ID depending on the record type.
2. All affected records have a "Company" value ("Account Name" value in SFDC).
3. Among the Lead type records that are affected, they are only bookings imported from a legacy system. While they obviously do not have an Account associated, they do have a "Company" value populated.
Here's an example of how the Activity Log looks (this record includes all 5 fields that are affected):
The individual Activity Details for one of the logged events looks like this:
The Marketo Integration User has full edit level permissions for 4 of the 5 fields on the Lead and Opp objects, and read permissions for the same 4 fields on the Contact object.
Thanks for assisting!