I see that periodically in Server 10. In my version, backups stop appearing once one of the schedules hangs in this state. I don't know if your experience will match mine given the different versions, but I find that I can select the files in the console window and set them to close. The console does not update to show them as closed, but I can then restart the server and this will clear up the issue until the next time a schedule hangs like this.
I know that the files have been closed successfully because the all re-open promptly after the restart. Before I figured out that I could actually close the files this way, I'd restart the server with them open and then one large multiple gigabyte file would spend about 15 to 20 minutes running a consistency check before it opened.