It’s very common for a ticket purchased on SeatGeek to have someone else’s name on it. This is usually the name of the person who originally purchased the ticket from the event box office (i.e. the primary market). By the time you see the ticket, it has been re-sold by that person at least once. Regardless of how many times a ticket changes hands, the name on it will not change.
Don’t worry. The name on your ticket has no bearing on whether you will be admitted to the event. The barcode is the only important piece of information on your ticket that will be scanned at the entrance.