Hi Felipe,
Thanks for that insight and your questions.
We don’t import data from the ISSN Portal directly, nor do we send data to them. The way a journal’s title is reflected in Crossref’s systems is entirely dependent on how that journal’s publisher/registrant sends it to us in the metadata deposits used to register their DOIs.
When you first deposit metadata for a given journal, the journal-level metadata - including the journal title, ISSN(s), journal-level DOI if you choose to register one - are used to form a title record for that journal in our system. That record is also ‘locked’ to the particular DOI prefix used in that first deposit as well.
We require that all future metadata deposits for that journal must contain journal-level metadata that matches the record established in our system by the first deposit. So, if you submit a journal title one way in the first deposit and then later switch to using a “parallel” or alternate title, the metadata deposit will fail with an error message that goes like <msg>ISSN "[ISSN]" has already been assigned, issn ([ISSN]) is assigned to another title ([title we have in our records])</msg>
Our documentation references the ISSN Centre’s policies because our system supports the principle that a substantive title change requires a new ISSN. But, that’s as far as we go with that.
If it turns out that you made a mistake in that first deposit, or you changed your title in a relatively minor way that doesn’t require a new ISSN, or you want to use an existing parallel title, we can modify the title record in our system for you. Just send us an email at support@crossref.org with the ISSN and new title before you submit the next metadata deposit for that journal.
Best,
Shayn