I see this error routinely when verifying older clones that have been in an offsite rotation.
The source is cloned nightly, without errors. Then when I verify the clone - I get this error. It repairs fine, and nightly backups continue then without error. Until the clone goes off site for some period of time.
See this thread:
http://www.shirt-pocket.com/forums/s...ead.php?t=1583
-Preston