I'm trying to use feeds + tamper to do bulk updates to an entity reference field in "Employee profile" content type but retaining existing values. I'm using a CSV file and mapping a "email" and "badge" columns as source with Email (field_email) and Badges (field_badges) as targets respectively, where email is set as unique. Additionally, I have configured the processor to "Do not update existing content items". When I run the import, it finishes successfully but it says "Feeds with tamper: There are no new Employee Profile items." and nothing is being added.
If I change the processor settings to "Update existing content items", the values are being added, but the existing ones are removed.
Any guidance will be appreciated.
Thanks in advance, Ruben B