If a ticket is in "feedback" state, it is waiting for feedback.
If it's in feedback state and someone confirms an issue is fixed, it can usually be closed. Often, though, the original problem description was a rare circumstance that requires feedback from someone with specific setups/traffic loads/etc so not just anyone can offer proper constructive feedback.
If you see a ticket in feedback state that looks like it should be closed, you might give it another try and then post more feedback on the ticket, or let us know specific ticket numbers that look like they can be closed.
Usually someone will periodically review the tickets in feedback state and close them as needed.