I don't think that's accurate. My understanding is that a Failed process in PA is still complete but it completed to the Red X exit operator instead of the green check. A blocked or suspended process would need to be repaired or cancelled. However, that being said, I would have expected a failed process to allow a ticket to be closed since it is no longer running.
The error about requiring a comment sounds like a status transition configuration moving from whatever status you were in to the Closed Status and shouldn't be directly related to the process itself. That's a configuration in Service Desk.