Why would OTBI reporting show a row with no absence plan name against an employee?

Summary:

Multiple rows showing with a blank Absence plan name

Content (required):

I have created a simple analysis with Person number, Name, Absence plan name and termination date and I am getting a lot of duplicate rows for people but there is no plan name in the row. Most people have a row with a plan name as well but some people only have a blank plan name.

All of the people reporting a blank plan name are enrolled on a plan in the front end of the system

Version (include the version you are using, if applicable):

21C

Code Snippet (add any code snippets that support your topic, if applicable):