Not sure if this is the right subforum or not...

We have our registration rules that list the the computers alias as follows: <Computer Name> - <IP Address>

On some PC's, we are getting duplicates; One with the above, and the other with <Computer Name> - <IP Address>-<Guid>

First, why is this? Second, how should we deal with it to prevent it? Third, should we delete or unregister the item with the GUID attached to the name?