So looking over logs today, I saw the following:
11/20/2012 6:02:52pm - Backup - Database backed up. Database... Pages dumped: 9218
11/20/2012 7:00:13pm - Backup - Database backed up. Database... Pages dumped: 9370
The first LSN and last LSN for both backups do NOT match.
The first backup event @ 6:02pm, the device is listed as a "Virtual_Device," while the 7pm backup went to disk.
I've checked all Agent jobs, and there is only one backup job, and it's scheduled to run at 6pm.
Finally, to play it safe, I attempted to restore from the backup file (one BAK and several Transaction Log backups from later) and had no problems.
So I don't think this is a problem, but I'm just curious as to what is causing this behavior.
Is the 6pm, which is going to the virtual device, a VSS snapshot, which is then being written into the final backup file?