In a "business project" using the filter shows users who are not in the project

[RR]

Within the top right of the list view for any project, it will show every single user within our site, including those that only have access to a service desk. is there a way to restrict this filter to only have access to the project? The users that show up do not have access to browse the project, nor are they assignable users.

[Mikael Sandberg]

What type of project is it, company managed or team managed? If it is a company managed project the assignee filter is based who have access to your instance, it is not just limited to who have access to the project.