In Blackbaud Sphere Thon events, teams can be created to group fundraisers for Sphere events. Team names must be unique. In this situation, your organization has found several teams with the same name.
The reason they were able to register with same name is because one entered 2 spaces between first and last name and the other entered 1. The system auto-corrects to remove the secondary space, so they look the same in reports/text values, although they were not originally entered exactly the same.