Unable to include an employee in New Mass Assignment process for Development Goal

Summary:

Am trying to setup the Development Goals Mass Assignment process. I get the following error when trying to add employees under the "Who do you want to include?" section.

{PERSON_NAME} is already included

Try selecting another person who needs to be assigned or shared the goals that are part of this mass process.

There are no other mass assignment processes and the person does not have any goals. Has anyone come across this issue?

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

24C (Redwood)

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