I recently moved a domain name in the Plesk 10 control panel from one subscription to another.
DNS is managed by another server so there is no change in DNS at all. The IP address is shared and remains the same so there is really no need for a DNS change.
But the domain is still managed by its former subscription (where it should have been removed from) and is pointing to exactly the same folder as in the past, even when is not in the list of domains there.
Subsequently, the new subscription do not have the domain under its control. Even this domain is in list of domains here and points to another folder.
Problem resolved: former administrator left wildcard ServerAlias in vhosts file in first subscription for this domain.
This vhosts file have been logically used by Apache before the new subscription could take care.
Removing this ServerAlias and restart Apache did the trick.