Salesforce Reports: Add to Campaign Button Adds All Lookup Column Records in Custom Report Types

When using a custom report type and clicking Add to Campaign, Salesforce adds records from all applicable lookup columns - including both Contact and Account lookups — rather than only the primary object's records. This can result in more campaign members being added than expected.

Steps to verify:

1. Create a custom report type with primary object as Contact.
2. Create a new report with the Custom Report Type. Add FirstName(contact) and Account Name (Account) fields in the report.
3. Click on "Add To Campaign" button and select a Campaign, click Submit.
4. It'll add all the Contact and Account records in the report as CampaignMembers.