Creating an Audience does not allow the selection of just one user if there are multiple users with the same name.
- Studio | People > Audiences
When creating an audience, if there are multiple users with the same name and you want to filter by Employee Name, the individuals with the same name are pulled together into one selectable user rather than individually:
The workaround for this issue is to build the group with another attribute such as email.
Please check the current status of this issue on the Known Issues Tracker. (Issue ID: CSUP-1677)