I know what you mean about it not being a server side issue. I think I was able to reproduce the issue perhaps because my vaultid or something changed when I moved my archive, rather than the issue was reproducable as a server issue.
In getting the sync doing more than it did before I have only done work on the client computers, nothing has changed on the servers.
All our EV servers are as identical as can be, all on the same build of Windows (2003 Enterprise x86), all on the same version of EV (8.0.5), etc.
So I am really the first person to come up against this issue?
Checking old entries here.
Was there not an issue where if Vault Cache was being built, and you moved the archive to another server, VC got messed up? Cannot find a technote, but did find some other forum entries.