This is also true with AFS 3.3. In personal email a few weeks ago, Dawn Johnson clearly stated that this would be fixed in AFS 3.3.
Dump is location independent at the user level.
If vos move can lock a volume's location, so can butc. Why should I have to look at this log at all. Then this is incorrect behaviour. Full backups take a long time here at Cranfield, and I know we're not that big a site. Go stick your head in a pig.