I’ve restored several VMs now, and it seems to be consistent that if I restore the tags then I get the CID mismatch, and if I don’t then it works fine. The ESXi 5.5U3 environment that I’m restoring into has a vCenter server, which is what I’m using as my target in Veeam.
To test things, I took another server identical to the ones in the 5.5 environment and did a test restore to it, both with and without tags. Both VMs powered up without issue. However, that was a standalone and did not have a vCenter server.