When I try to register the account "User:Pine W" I am told that it is too similar to "User:Pinew". However, a search of the list of users on Meta shows that "User:Pinew" does not exist. Is there someplace else in the Wikiverse that this account exists or is there a bug here?
There is a user named "Pinew", registered on Turkish Wikipedia: https://meta.wikimedia.org/wiki/Special:CentralAuth/Pinew. As all accounts are now global, you can't register that username (or similar usernames blocked by AntiSpoof) on any Wikimedia wiki.
(If you ask an administrator, they can create the account "Pine W" for you, they can override the AntiSpoof error using an extra checkbox on the signup form.)