Just did some more research on this issue and this is what I found out:
It seems that EMC is searching for the machine SID (and not the DOMAIN SID for that computer) - probably as a bug fix to the KB981033 issue (customers who put dots in their computer Netbios names - who would ever do that?!#.)
In my case the machine SID was the same on all virtual servers:
S-1-5-21-401783670-1437582426-1158247984
(same result you get when running psgetsid without any parameters)
All my virtual machines were of course cloned before they ever joined a domain. As my child wisdom told me a machine will get a unique domain SID when it's joined to a domain - even when several machines with the same machine SID are joined to a domain they will always get a unique domain SID. Hence when I run:
psgetsid DOMAINMACHINEACCOUNT$
The results are all different:
DC1:
S-1-5-21-401783670-1437582426-1158247984-1000
DC2:
S-1-5-21-401783670-1437582426-1158247984-1103
MAIL1:
S-1-5-21-401783670-1437582426-1158247984-1105
MAIL2:
S-1-5-21-401783670-1437582426-1158247984-1104
MAIL3:
S-1-5-21-401783670-1437582426-1158247984-1601
When I go through adsiedit and check the "objectSid" attribute of all the computer accounts they are indeed the same unique values that psgetsid DOMAINCOMPUTERNAME$ gave me from the command line.
It clearly looks as this is a huge bug in the EMC. The search that it does in the background should have been based on a full ldap-path, objectSid (the domain one), objectGUID or something else than the local machine SID.