Salesforce: Opportunity in Campaign

Last year, we wrote a blog about what happens when we convert a Lead to an Account and Opportunity, and how it reflects in Campaign Influence & Primary Campaign Source in Opportunity.

You will notice that the Primary Campaign Source field in Opportunity is always the same as the selected Primary Campaign Source in Campaign Influence. But only one campaign can be marked as Primary Campaign Source in Opportunity.

From the above screenshot, you can see two campaigns related in Opportunity Opty Hello, but My One is the one marked as Primary Campaign Source.

Now, if we go to Campaign and look for both campaigns above. There is an Opportunity related list in the Campaign. But only in the campaign selected as Primary Campaign Source (for this case, My One), the Opportunity will be displayed. For the other campaign, You Two, although it is listed in the Opportunity page layout, it will not be shown in Campaign because it is not the Primary Campaign Source.

This is out-of-the-box Salesforce functionality, and there is no way to modify it unless you totally do not want to use Campaign Influence & Primary Campaign Source; you can create a junction object to relate Campaign and Opportunity.

Reference: What is Campaign Influence?