Partial Data Issue in Insight Report When Combining Contact with Email Open and Form Submission

I am currently building a custom report in Eloqua Insight with the following requirements:

• Contact information, including lead score (already available in the Contact subject area)
• Email open activities associated with each contact
• Form submissions made by those contacts

The objective is to analyze user behavior by linking lead scores with email engagement and form submissions, using email address as the common identifier.

Here’s the issue I’m encountering:
When I run a report using only the Contact subject area, I can see all 350 records as expected.
However, when I include additional subject areas such as Email Open or